2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Tetsuo Handa <[email protected]> If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer dereference happens upon core dump because argv_split("") returns argv[0] == NULL. This bug was once fixed by commit 264b83c07a84 ("usermodehelper: check subprocess_info->path != NULL") but was by error reintroduced by commit 7f57cfa4e2aa ("usermodehelper: kill the sub_info->path[0] check"). This bug seems to exist since 2.6.19 (the version which core dump to pipe was added). Depending on kernel version and config, some side effect might happen immediately after this oops (e.g. kernel panic with 2.6.32-358.18.1.el6). Signed-off-by: Tetsuo Handa <[email protected]> Acked-by: Oleg Nesterov <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> (cherry picked from commit 4c1c7be95c345cf2ad537a0c48e9aeadc7304527) Signed-off-by: Willy Tarreau <[email protected]> --- kernel/kmod.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/kmod.c b/kernel/kmod.c index 8ecc509..3da09a9 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -560,6 +560,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, BUG_ON(atomic_read(&sub_info->cred->usage) != 1); validate_creds(sub_info->cred); + if (!sub_info->path) { + call_usermodehelper_freeinfo(sub_info); + return -EINVAL; + } helper_lock(); if (sub_info->path[0] == '\0') goto out; -- 1.7.12.2.21.g234cd45.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
