diff options
author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
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committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
commit | 135d39dcedcedd1f44ea0bba52f15ac5922c114f (patch) | |
tree | 12379fc8ef7489eaca1c7245f8bd6af74c619a8f /fs/binfmt_script.c | |
parent | 187764bd111b27783b6d68ffb3b3dbb3a9bafd38 (diff) | |
parent | 1279cd128bba968ebe0a2df7f7ae38bae90250ef (diff) |
Merge remote-tracking branch 'remotes/fslc/4.9-2.3.x-imx' into toradex_4.9-2.3.x-imx-next
Conflicts:
sound/soc/codecs/sgtl5000.c
sound/soc/fsl/imx-sgtl5000.c
Diffstat (limited to 'fs/binfmt_script.c')
-rw-r--r-- | fs/binfmt_script.c | 57 |
1 files changed, 48 insertions, 9 deletions
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c index afdf4e3cafc2..37c2093a24d3 100644 --- a/fs/binfmt_script.c +++ b/fs/binfmt_script.c @@ -14,14 +14,31 @@ #include <linux/err.h> #include <linux/fs.h> +static inline bool spacetab(char c) { return c == ' ' || c == '\t'; } +static inline char *next_non_spacetab(char *first, const char *last) +{ + for (; first <= last; first++) + if (!spacetab(*first)) + return first; + return NULL; +} +static inline char *next_terminator(char *first, const char *last) +{ + for (; first <= last; first++) + if (spacetab(*first) || !*first) + return first; + return NULL; +} + static int load_script(struct linux_binprm *bprm) { const char *i_arg, *i_name; - char *cp; + char *cp, *buf_end; struct file *file; char interp[BINPRM_BUF_SIZE]; int retval; + /* Not ours to exec if we don't start with "#!". */ if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!')) return -ENOEXEC; @@ -34,18 +51,40 @@ static int load_script(struct linux_binprm *bprm) if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) return -ENOENT; - /* - * This section does the #! interpretation. - * Sorta complicated, but hopefully it will work. -TYT - */ - + /* Release since we are not mapping a binary into memory. */ allow_write_access(bprm->file); fput(bprm->file); bprm->file = NULL; - bprm->buf[BINPRM_BUF_SIZE - 1] = '\0'; - if ((cp = strchr(bprm->buf, '\n')) == NULL) - cp = bprm->buf+BINPRM_BUF_SIZE-1; + /* + * This section handles parsing the #! line into separate + * interpreter path and argument strings. We must be careful + * because bprm->buf is not yet guaranteed to be NUL-terminated + * (though the buffer will have trailing NUL padding when the + * file size was smaller than the buffer size). + * + * We do not want to exec a truncated interpreter path, so either + * we find a newline (which indicates nothing is truncated), or + * we find a space/tab/NUL after the interpreter path (which + * itself may be preceded by spaces/tabs). Truncating the + * arguments is fine: the interpreter can re-read the script to + * parse them on its own. + */ + buf_end = bprm->buf + sizeof(bprm->buf) - 1; + cp = strnchr(bprm->buf, sizeof(bprm->buf), '\n'); + if (!cp) { + cp = next_non_spacetab(bprm->buf + 2, buf_end); + if (!cp) + return -ENOEXEC; /* Entire buf is spaces/tabs */ + /* + * If there is no later space/tab/NUL we must assume the + * interpreter path is truncated. + */ + if (!next_terminator(cp, buf_end)) + return -ENOEXEC; + cp = buf_end; + } + /* NUL-terminate the buffer and any trailing spaces/tabs. */ *cp = '\0'; while (cp > bprm->buf) { cp--; |