From 8c9e80ed276fc4b9c9fadf29d8bf6b3576112f1a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 21 Apr 2011 17:23:19 -0700 Subject: SECURITY: Move exec_permission RCU checks into security modules Right now all RCU walks fall back to reference walk when CONFIG_SECURITY is enabled, even though just the standard capability module is active. This is because security_inode_exec_permission unconditionally fails RCU walks. Move this decision to the low level security module. This requires passing the RCU flags down the security hook. This way at least the capability module and a few easy cases in selinux/smack work with RCU walks with CONFIG_SECURITY=y Signed-off-by: Andi Kleen Acked-by: Eric Paris Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f9c3764e4859..a73f4e463774 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2635,7 +2635,7 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *na return dentry_has_perm(cred, NULL, dentry, FILE__READ); } -static int selinux_inode_permission(struct inode *inode, int mask) +static int selinux_inode_permission(struct inode *inode, int mask, unsigned flags) { const struct cred *cred = current_cred(); struct common_audit_data ad; @@ -2649,6 +2649,10 @@ static int selinux_inode_permission(struct inode *inode, int mask) if (!mask) return 0; + /* May be droppable after audit */ + if (flags & IPERM_FLAG_RCU) + return -ECHILD; + COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; -- cgit v1.2.3 From a35c6c8368d88deae6890205e73ed330b6df1db7 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Wed, 20 Apr 2011 10:21:28 -0400 Subject: SELinux: silence build warning when !CONFIG_BUG If one builds a kernel without CONFIG_BUG there are a number of 'may be used uninitialized' warnings. Silence these by returning after the BUG(). Signed-off-by: Eric Paris Reviewed-by: James Morris --- security/selinux/hooks.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d52a92507412..7a630a8a5cef 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -989,6 +989,7 @@ static void selinux_write_opts(struct seq_file *m, continue; default: BUG(); + return; }; /* we need a comma before each option */ seq_putc(m, ','); @@ -1442,6 +1443,7 @@ static int task_has_capability(struct task_struct *tsk, printk(KERN_ERR "SELinux: out of range capability %d\n", cap); BUG(); + return -EINVAL; } rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd); -- cgit v1.2.3 From 1c9904297451f558191e211a48d8838b4bf792b0 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 21 Apr 2011 17:23:19 -0700 Subject: SECURITY: Move exec_permission RCU checks into security modules Right now all RCU walks fall back to reference walk when CONFIG_SECURITY is enabled, even though just the standard capability module is active. This is because security_inode_exec_permission unconditionally fails RCU walks. Move this decision to the low level security module. This requires passing the RCU flags down the security hook. This way at least the capability module and a few easy cases in selinux/smack work with RCU walks with CONFIG_SECURITY=y Signed-off-by: Andi Kleen Signed-off-by: Eric Paris --- security/selinux/hooks.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 7a630a8a5cef..9a220be17a3f 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2635,7 +2635,7 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *na return dentry_has_perm(cred, NULL, dentry, FILE__READ); } -static int selinux_inode_permission(struct inode *inode, int mask) +static int selinux_inode_permission(struct inode *inode, int mask, unsigned flags) { const struct cred *cred = current_cred(); struct common_audit_data ad; @@ -2649,6 +2649,10 @@ static int selinux_inode_permission(struct inode *inode, int mask) if (!mask) return 0; + /* May be droppable after audit */ + if (flags & IPERM_FLAG_RCU) + return -ECHILD; + COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; -- cgit v1.2.3 From 0dc1ba24f7fff659725eecbba2c9ad679a0954cd Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 Apr 2011 17:23:20 -0700 Subject: SELINUX: Make selinux cache VFS RCU walks safe Now that the security modules can decide whether they support the dcache RCU walk or not it's possible to make selinux a bit more RCU friendly. The SELinux AVC and security server access decision code is RCU safe. A specific piece of the LSM audit code may not be RCU safe. This patch makes the VFS RCU walk retry if it would hit the non RCU safe chunk of code. It will normally just work under RCU. This is done simply by passing the VFS RCU state as a flag down into the avc_audit() code and returning ECHILD there if it would have an issue. Based-on-patch-by: Andi Kleen Signed-off-by: Eric Paris --- security/selinux/hooks.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9a220be17a3f..ed5f29aa0a38 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1447,8 +1447,11 @@ static int task_has_capability(struct task_struct *tsk, } rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd); - if (audit == SECURITY_CAP_AUDIT) - avc_audit(sid, sid, sclass, av, &avd, rc, &ad); + if (audit == SECURITY_CAP_AUDIT) { + int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0); + if (rc2) + return rc2; + } return rc; } @@ -1468,7 +1471,8 @@ static int task_has_system(struct task_struct *tsk, static int inode_has_perm(const struct cred *cred, struct inode *inode, u32 perms, - struct common_audit_data *adp) + struct common_audit_data *adp, + unsigned flags) { struct inode_security_struct *isec; struct common_audit_data ad; @@ -1488,7 +1492,7 @@ static int inode_has_perm(const struct cred *cred, ad.u.fs.inode = inode; } - return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp); + return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); } /* Same as inode_has_perm, but pass explicit audit data containing @@ -1505,7 +1509,7 @@ static inline int dentry_has_perm(const struct cred *cred, COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.path.mnt = mnt; ad.u.fs.path.dentry = dentry; - return inode_has_perm(cred, inode, av, &ad); + return inode_has_perm(cred, inode, av, &ad, 0); } /* Check whether a task can use an open file descriptor to @@ -1541,7 +1545,7 @@ static int file_has_perm(const struct cred *cred, /* av is zero if only checking access to the descriptor. */ rc = 0; if (av) - rc = inode_has_perm(cred, inode, av, &ad); + rc = inode_has_perm(cred, inode, av, &ad, 0); out: return rc; @@ -2103,7 +2107,7 @@ static inline void flush_unauthorized_files(const struct cred *cred, file = file_priv->file; inode = file->f_path.dentry->d_inode; if (inode_has_perm(cred, inode, - FILE__READ | FILE__WRITE, NULL)) { + FILE__READ | FILE__WRITE, NULL, 0)) { drop_tty = 1; } } @@ -2649,10 +2653,6 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag if (!mask) return 0; - /* May be droppable after audit */ - if (flags & IPERM_FLAG_RCU) - return -ECHILD; - COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; @@ -2661,7 +2661,7 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag perms = file_mask_to_av(inode->i_mode, mask); - return inode_has_perm(cred, inode, perms, &ad); + return inode_has_perm(cred, inode, perms, &ad, flags); } static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) @@ -3208,7 +3208,7 @@ static int selinux_dentry_open(struct file *file, const struct cred *cred) * new inode label or new policy. * This check is not redundant - do not remove. */ - return inode_has_perm(cred, inode, open_file_to_av(file), NULL); + return inode_has_perm(cred, inode, open_file_to_av(file), NULL, 0); } /* task security operations */ -- cgit v1.2.3 From f48b7399840b453e7282b523f535561fe9638a2d Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 25 Apr 2011 12:54:27 -0400 Subject: LSM: split LSM_AUDIT_DATA_FS into _PATH and _INODE The lsm common audit code has wacky contortions making sure which pieces of information are set based on if it was given a path, dentry, or inode. Split this into path and inode to get rid of some of the code complexity. Signed-off-by: Eric Paris Acked-by: Casey Schaufler --- security/selinux/hooks.c | 50 ++++++++++++++++++++++++------------------------ 1 file changed, 25 insertions(+), 25 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ed5f29aa0a38..ad664d3056eb 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1488,8 +1488,8 @@ static int inode_has_perm(const struct cred *cred, if (!adp) { adp = &ad; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.inode = inode; + COMMON_AUDIT_DATA_INIT(&ad, INODE); + ad.u.inode = inode; } return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); @@ -1506,9 +1506,9 @@ static inline int dentry_has_perm(const struct cred *cred, struct inode *inode = dentry->d_inode; struct common_audit_data ad; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.mnt = mnt; - ad.u.fs.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.mnt = mnt; + ad.u.path.dentry = dentry; return inode_has_perm(cred, inode, av, &ad, 0); } @@ -1530,8 +1530,8 @@ static int file_has_perm(const struct cred *cred, u32 sid = cred_sid(cred); int rc; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path = file->f_path; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path = file->f_path; if (sid != fsec->sid) { rc = avc_has_perm(sid, fsec->sid, @@ -1569,8 +1569,8 @@ static int may_create(struct inode *dir, sid = tsec->sid; newsid = tsec->create_sid; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.dentry = dentry; rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, DIR__ADD_NAME | DIR__SEARCH, @@ -1621,8 +1621,8 @@ static int may_link(struct inode *dir, dsec = dir->i_security; isec = dentry->d_inode->i_security; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.dentry = dentry; av = DIR__SEARCH; av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME); @@ -1667,9 +1667,9 @@ static inline int may_rename(struct inode *old_dir, old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode); new_dsec = new_dir->i_security; - COMMON_AUDIT_DATA_INIT(&ad, FS); + COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.fs.path.dentry = old_dentry; + ad.u.path.dentry = old_dentry; rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR, DIR__REMOVE_NAME | DIR__SEARCH, &ad); if (rc) @@ -1685,7 +1685,7 @@ static inline int may_rename(struct inode *old_dir, return rc; } - ad.u.fs.path.dentry = new_dentry; + ad.u.path.dentry = new_dentry; av = DIR__ADD_NAME | DIR__SEARCH; if (new_dentry->d_inode) av |= DIR__REMOVE_NAME; @@ -1991,8 +1991,8 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) return rc; } - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path = bprm->file->f_path; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path = bprm->file->f_path; if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) new_tsec->sid = old_tsec->sid; @@ -2120,7 +2120,7 @@ static inline void flush_unauthorized_files(const struct cred *cred, /* Revalidate access to inherited open files. */ - COMMON_AUDIT_DATA_INIT(&ad, FS); + COMMON_AUDIT_DATA_INIT(&ad, INODE); spin_lock(&files->file_lock); for (;;) { @@ -2468,8 +2468,8 @@ static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data) if (flags & MS_KERNMOUNT) return 0; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.dentry = sb->s_root; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.dentry = sb->s_root; return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad); } @@ -2478,8 +2478,8 @@ static int selinux_sb_statfs(struct dentry *dentry) const struct cred *cred = current_cred(); struct common_audit_data ad; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.dentry = dentry->d_sb->s_root; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.dentry = dentry->d_sb->s_root; return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad); } @@ -2653,8 +2653,8 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag if (!mask) return 0; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.inode = inode; + COMMON_AUDIT_DATA_INIT(&ad, INODE); + ad.u.inode = inode; if (from_access) ad.selinux_audit_data.auditdeny |= FILE__AUDIT_ACCESS; @@ -2732,8 +2732,8 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name, if (!is_owner_or_cap(inode)) return -EPERM; - COMMON_AUDIT_DATA_INIT(&ad, FS); - ad.u.fs.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, PATH); + ad.u.path.dentry = dentry; rc = avc_has_perm(sid, isec->sid, isec->sclass, FILE__RELABELFROM, &ad); -- cgit v1.2.3 From a269434d2fb48a4d66c1d7bf821b7874b59c5b41 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 25 Apr 2011 13:10:27 -0400 Subject: LSM: separate LSM_AUDIT_DATA_DENTRY from LSM_AUDIT_DATA_PATH This patch separates and audit message that only contains a dentry from one that contains a full path. This allows us to make it harder to misuse the interfaces or for the interfaces to be implemented wrong. Signed-off-by: Eric Paris Acked-by: Casey Schaufler --- security/selinux/hooks.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ad664d3056eb..9e8078a42a94 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1569,8 +1569,8 @@ static int may_create(struct inode *dir, sid = tsec->sid; newsid = tsec->create_sid; - COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = dentry; rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, DIR__ADD_NAME | DIR__SEARCH, @@ -1621,8 +1621,8 @@ static int may_link(struct inode *dir, dsec = dir->i_security; isec = dentry->d_inode->i_security; - COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = dentry; av = DIR__SEARCH; av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME); @@ -1667,9 +1667,9 @@ static inline int may_rename(struct inode *old_dir, old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode); new_dsec = new_dir->i_security; - COMMON_AUDIT_DATA_INIT(&ad, PATH); + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); - ad.u.path.dentry = old_dentry; + ad.u.dentry = old_dentry; rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR, DIR__REMOVE_NAME | DIR__SEARCH, &ad); if (rc) @@ -1685,7 +1685,7 @@ static inline int may_rename(struct inode *old_dir, return rc; } - ad.u.path.dentry = new_dentry; + ad.u.dentry = new_dentry; av = DIR__ADD_NAME | DIR__SEARCH; if (new_dentry->d_inode) av |= DIR__REMOVE_NAME; @@ -2468,8 +2468,8 @@ static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data) if (flags & MS_KERNMOUNT) return 0; - COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.dentry = sb->s_root; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = sb->s_root; return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad); } @@ -2478,8 +2478,8 @@ static int selinux_sb_statfs(struct dentry *dentry) const struct cred *cred = current_cred(); struct common_audit_data ad; - COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.dentry = dentry->d_sb->s_root; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = dentry->d_sb->s_root; return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad); } @@ -2732,8 +2732,8 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name, if (!is_owner_or_cap(inode)) return -EPERM; - COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.dentry = dentry; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = dentry; rc = avc_has_perm(sid, isec->sid, isec->sclass, FILE__RELABELFROM, &ad); -- cgit v1.2.3 From 9ade0cf440a1e5800dc68eef2e77b8d9d83a6dff Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 25 Apr 2011 16:26:29 -0400 Subject: SELINUX: Make selinux cache VFS RCU walks safe Now that the security modules can decide whether they support the dcache RCU walk or not it's possible to make selinux a bit more RCU friendly. The SELinux AVC and security server access decision code is RCU safe. A specific piece of the LSM audit code may not be RCU safe. This patch makes the VFS RCU walk retry if it would hit the non RCU safe chunk of code. It will normally just work under RCU. This is done simply by passing the VFS RCU state as a flag down into the avc_audit() code and returning ECHILD there if it would have an issue. Based-on-patch-by: Andi Kleen Signed-off-by: Eric Paris Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a73f4e463774..f7cf0ea6faea 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1446,8 +1446,11 @@ static int task_has_capability(struct task_struct *tsk, } rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd); - if (audit == SECURITY_CAP_AUDIT) - avc_audit(sid, sid, sclass, av, &avd, rc, &ad); + if (audit == SECURITY_CAP_AUDIT) { + int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0); + if (rc2) + return rc2; + } return rc; } @@ -1467,7 +1470,8 @@ static int task_has_system(struct task_struct *tsk, static int inode_has_perm(const struct cred *cred, struct inode *inode, u32 perms, - struct common_audit_data *adp) + struct common_audit_data *adp, + unsigned flags) { struct inode_security_struct *isec; struct common_audit_data ad; @@ -1487,7 +1491,7 @@ static int inode_has_perm(const struct cred *cred, ad.u.fs.inode = inode; } - return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp); + return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); } /* Same as inode_has_perm, but pass explicit audit data containing @@ -1504,7 +1508,7 @@ static inline int dentry_has_perm(const struct cred *cred, COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.path.mnt = mnt; ad.u.fs.path.dentry = dentry; - return inode_has_perm(cred, inode, av, &ad); + return inode_has_perm(cred, inode, av, &ad, 0); } /* Check whether a task can use an open file descriptor to @@ -1540,7 +1544,7 @@ static int file_has_perm(const struct cred *cred, /* av is zero if only checking access to the descriptor. */ rc = 0; if (av) - rc = inode_has_perm(cred, inode, av, &ad); + rc = inode_has_perm(cred, inode, av, &ad, 0); out: return rc; @@ -2103,7 +2107,7 @@ static inline void flush_unauthorized_files(const struct cred *cred, file = file_priv->file; inode = file->f_path.dentry->d_inode; if (inode_has_perm(cred, inode, - FILE__READ | FILE__WRITE, NULL)) { + FILE__READ | FILE__WRITE, NULL, 0)) { drop_tty = 1; } } @@ -2649,10 +2653,6 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag if (!mask) return 0; - /* May be droppable after audit */ - if (flags & IPERM_FLAG_RCU) - return -ECHILD; - COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; @@ -2661,7 +2661,7 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag perms = file_mask_to_av(inode->i_mode, mask); - return inode_has_perm(cred, inode, perms, &ad); + return inode_has_perm(cred, inode, perms, &ad, flags); } static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) @@ -3209,7 +3209,7 @@ static int selinux_dentry_open(struct file *file, const struct cred *cred) * new inode label or new policy. * This check is not redundant - do not remove. */ - return inode_has_perm(cred, inode, open_file_to_av(file), NULL); + return inode_has_perm(cred, inode, open_file_to_av(file), NULL, 0); } /* task security operations */ -- cgit v1.2.3 From 562abf624175e3f8487b7f064e516805e437e597 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:11:21 -0400 Subject: SELinux: pass last path component in may_create New inodes are created in a two stage process. We first will compute the label on a new inode in security_inode_create() and check if the operation is allowed. We will then actually re-compute that same label and apply it in security_inode_init_security(). The change to do new label calculations based in part on the last component of the path name only passed the path component information all the way down the security_inode_init_security hook. Down the security_inode_create hook the path information did not make it past may_create. Thus the two calculations came up differently and the permissions check might not actually be against the label that is created. Pass and use the same information in both places to harmonize the calculations and checks. Reported-by: Dominick Grift Signed-off-by: Eric Paris --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9e8078a42a94..a6dd2bed8d7b 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1579,7 +1579,8 @@ static int may_create(struct inode *dir, return rc; if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { - rc = security_transition_sid(sid, dsec->sid, tclass, NULL, &newsid); + rc = security_transition_sid(sid, dsec->sid, tclass, + &dentry->d_name, &newsid); if (rc) return rc; } -- cgit v1.2.3 From 2875fa00830be62431f5ac22d8f85d57f9fa3033 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 16:04:24 -0400 Subject: SELinux: introduce path_has_perm We currently have inode_has_perm and dentry_has_perm. dentry_has_perm just calls inode_has_perm with additional audit data. But dentry_has_perm can take either a dentry or a path. Split those to make the code obvious and to fix the previous problem where I thought dentry_has_perm always had a valid dentry and mnt. Signed-off-by: Eric Paris --- security/selinux/hooks.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a6dd2bed8d7b..9f426b8a12b5 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1499,16 +1499,29 @@ static int inode_has_perm(const struct cred *cred, the dentry to help the auditing code to more easily generate the pathname if needed. */ static inline int dentry_has_perm(const struct cred *cred, - struct vfsmount *mnt, struct dentry *dentry, u32 av) { struct inode *inode = dentry->d_inode; struct common_audit_data ad; + COMMON_AUDIT_DATA_INIT(&ad, DENTRY); + ad.u.dentry = dentry; + return inode_has_perm(cred, inode, av, &ad, 0); +} + +/* Same as inode_has_perm, but pass explicit audit data containing + the path to help the auditing code to more easily generate the + pathname if needed. */ +static inline int path_has_perm(const struct cred *cred, + struct path *path, + u32 av) +{ + struct inode *inode = path->dentry->d_inode; + struct common_audit_data ad; + COMMON_AUDIT_DATA_INIT(&ad, PATH); - ad.u.path.mnt = mnt; - ad.u.path.dentry = dentry; + ad.u.path = *path; return inode_has_perm(cred, inode, av, &ad, 0); } @@ -1896,7 +1909,7 @@ static int selinux_quota_on(struct dentry *dentry) { const struct cred *cred = current_cred(); - return dentry_has_perm(cred, NULL, dentry, FILE__QUOTAON); + return dentry_has_perm(cred, dentry, FILE__QUOTAON); } static int selinux_syslog(int type) @@ -2496,8 +2509,7 @@ static int selinux_mount(char *dev_name, return superblock_has_perm(cred, path->mnt->mnt_sb, FILESYSTEM__REMOUNT, NULL); else - return dentry_has_perm(cred, path->mnt, path->dentry, - FILE__MOUNTON); + return path_has_perm(cred, path, FILE__MOUNTON); } static int selinux_umount(struct vfsmount *mnt, int flags) @@ -2630,14 +2642,14 @@ static int selinux_inode_readlink(struct dentry *dentry) { const struct cred *cred = current_cred(); - return dentry_has_perm(cred, NULL, dentry, FILE__READ); + return dentry_has_perm(cred, dentry, FILE__READ); } static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata) { const struct cred *cred = current_cred(); - return dentry_has_perm(cred, NULL, dentry, FILE__READ); + return dentry_has_perm(cred, dentry, FILE__READ); } static int selinux_inode_permission(struct inode *inode, int mask, unsigned flags) @@ -2680,16 +2692,20 @@ static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) - return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR); + return dentry_has_perm(cred, dentry, FILE__SETATTR); - return dentry_has_perm(cred, NULL, dentry, FILE__WRITE); + return dentry_has_perm(cred, dentry, FILE__WRITE); } static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry) { const struct cred *cred = current_cred(); + struct path path; + + path.dentry = dentry; + path.mnt = mnt; - return dentry_has_perm(cred, mnt, dentry, FILE__GETATTR); + return path_has_perm(cred, &path, FILE__GETATTR); } static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name) @@ -2710,7 +2726,7 @@ static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name) /* Not an attribute we recognize, so just check the ordinary setattr permission. */ - return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR); + return dentry_has_perm(cred, dentry, FILE__SETATTR); } static int selinux_inode_setxattr(struct dentry *dentry, const char *name, @@ -2797,14 +2813,14 @@ static int selinux_inode_getxattr(struct dentry *dentry, const char *name) { const struct cred *cred = current_cred(); - return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR); + return dentry_has_perm(cred, dentry, FILE__GETATTR); } static int selinux_inode_listxattr(struct dentry *dentry) { const struct cred *cred = current_cred(); - return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR); + return dentry_has_perm(cred, dentry, FILE__GETATTR); } static int selinux_inode_removexattr(struct dentry *dentry, const char *name) -- cgit v1.2.3 From cb1e922fa104bb0bb3aa5fc6ca7f7e070f3b55e9 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:11:21 -0400 Subject: SELinux: pass last path component in may_create New inodes are created in a two stage process. We first will compute the label on a new inode in security_inode_create() and check if the operation is allowed. We will then actually re-compute that same label and apply it in security_inode_init_security(). The change to do new label calculations based in part on the last component of the path name only passed the path component information all the way down the security_inode_init_security hook. Down the security_inode_create hook the path information did not make it past may_create. Thus the two calculations came up differently and the permissions check might not actually be against the label that is created. Pass and use the same information in both places to harmonize the calculations and checks. Reported-by: Dominick Grift Signed-off-by: Eric Paris --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d52a92507412..9a93af81a0c3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1573,7 +1573,8 @@ static int may_create(struct inode *dir, return rc; if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { - rc = security_transition_sid(sid, dsec->sid, tclass, NULL, &newsid); + rc = security_transition_sid(sid, dsec->sid, tclass, + &dentry->d_name, &newsid); if (rc) return rc; } -- cgit v1.2.3 From 95f4efb2d78661065aaf0be57f5bf00e4d2aea1d Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 8 Jun 2011 15:11:56 -0700 Subject: selinux: simplify and clean up inode_has_perm() This is a rather hot function that is called with a potentially NULL "struct common_audit_data" pointer argument. And in that case it has to provide and initialize its own dummy common_audit_data structure. However, all the _common_ cases already pass it a real audit-data structure, so that uncommon NULL case not only creates a silly run-time test, more importantly it causes that function to have a big stack frame for the dummy variable that isn't even used in the common case! So get rid of that stupid run-time behavior, and make the (few) functions that currently call with a NULL pointer just call a new helper function instead (naturally called inode_has_perm_noapd(), since it has no adp argument). This makes the run-time test be a static code generation issue instead, and allows for a much denser stack since none of the common callers need the dummy structure. And a denser stack not only means less stack space usage, it means better cache behavior. So we have a win-win-win from this simplification: less code executed, smaller stack footprint, and better cache behavior. Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a0d38459d650..20219ef5439a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1476,7 +1476,6 @@ static int inode_has_perm(const struct cred *cred, unsigned flags) { struct inode_security_struct *isec; - struct common_audit_data ad; u32 sid; validate_creds(cred); @@ -1487,15 +1486,21 @@ static int inode_has_perm(const struct cred *cred, sid = cred_sid(cred); isec = inode->i_security; - if (!adp) { - adp = &ad; - COMMON_AUDIT_DATA_INIT(&ad, INODE); - ad.u.inode = inode; - } - return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); } +static int inode_has_perm_noadp(const struct cred *cred, + struct inode *inode, + u32 perms, + unsigned flags) +{ + struct common_audit_data ad; + + COMMON_AUDIT_DATA_INIT(&ad, INODE); + ad.u.inode = inode; + return inode_has_perm(cred, inode, perms, &ad, flags); +} + /* Same as inode_has_perm, but pass explicit audit data containing the dentry to help the auditing code to more easily generate the pathname if needed. */ @@ -2122,8 +2127,8 @@ static inline void flush_unauthorized_files(const struct cred *cred, struct tty_file_private, list); file = file_priv->file; inode = file->f_path.dentry->d_inode; - if (inode_has_perm(cred, inode, - FILE__READ | FILE__WRITE, NULL, 0)) { + if (inode_has_perm_noadp(cred, inode, + FILE__READ | FILE__WRITE, 0)) { drop_tty = 1; } } @@ -3228,7 +3233,7 @@ static int selinux_dentry_open(struct file *file, const struct cred *cred) * new inode label or new policy. * This check is not redundant - do not remove. */ - return inode_has_perm(cred, inode, open_file_to_av(file), NULL, 0); + return inode_has_perm_noadp(cred, inode, open_file_to_av(file), 0); } /* task security operations */ -- cgit v1.2.3