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author | Andreas Schwab <schwab@suse.de> | 2020-02-19 17:21:46 +0100 |
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committer | Patsy Franklin <patsy@redhat.com> | 2020-03-17 21:51:11 -0400 |
commit | 9aaebaf805f24ae10e0bfad332d6d5eabd58c451 (patch) | |
tree | ba002a25e02d8518211648307f4ded17985aab00 | |
parent | 8e5d591b101d7d8a4628522f1e5ec24b6dfa731b (diff) | |
download | glibc-9aaebaf805f24ae10e0bfad332d6d5eabd58c451.tar.gz |
Fix use-after-free in glob when expanding ~user (bug 25414)
The value of `end_name' points into the value of `dirname', thus don't
deallocate the latter before the last use of the former.
(cherry picked from commit ddc650e9b3dc916eab417ce9f79e67337b05035c)
-rw-r--r-- | posix/glob.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/posix/glob.c b/posix/glob.c index e73e35c510..c6cbd0eb43 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int), { size_t home_len = strlen (p->pw_dir); size_t rest_len = end_name == NULL ? 0 : strlen (end_name); - char *d; + char *d, *newp; + bool use_alloca = glob_use_alloca (alloca_used, + home_len + rest_len + 1); - if (__glibc_unlikely (malloc_dirname)) - free (dirname); - malloc_dirname = 0; - - if (glob_use_alloca (alloca_used, home_len + rest_len + 1)) - dirname = alloca_account (home_len + rest_len + 1, - alloca_used); + if (use_alloca) + newp = alloca_account (home_len + rest_len + 1, alloca_used); else { - dirname = malloc (home_len + rest_len + 1); - if (dirname == NULL) + newp = malloc (home_len + rest_len + 1); + if (newp == NULL) { scratch_buffer_free (&pwtmpbuf); retval = GLOB_NOSPACE; goto out; } - malloc_dirname = 1; } - d = mempcpy (dirname, p->pw_dir, home_len); + d = mempcpy (newp, p->pw_dir, home_len); if (end_name != NULL) d = mempcpy (d, end_name, rest_len); *d = '\0'; + if (__glibc_unlikely (malloc_dirname)) + free (dirname); + dirname = newp; + malloc_dirname = !use_alloca; + dirlen = home_len + rest_len; dirname_modified = 1; } |