From e9cd2e2bd9ec91a0b1050c4aa79555d142985924 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 31 Mar 2016 11:45:55 +0200 Subject: libmount: Fix possible NULL dereference in get_btrfs_fs_root() The function mnt_table_get_fs_root() should be robust enough to accept NULL as mountinfo -- the right behaviour is to default to '/'. The set_fs_root() (tab_update.c) has to understand when mountinfo is necessary (for bind mounts and btrfs). Reported-by: Stanislav Brabec Signed-off-by: Karel Zak --- libmount/src/tab_update.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'libmount/src/tab_update.c') diff --git a/libmount/src/tab_update.c b/libmount/src/tab_update.c index 40adba98a..631e1cd9f 100644 --- a/libmount/src/tab_update.c +++ b/libmount/src/tab_update.c @@ -357,7 +357,7 @@ static int set_fs_root(struct libmnt_update *upd, struct libmnt_fs *fs, { struct libmnt_fs *src_fs; char *fsroot = NULL; - const char *src; + const char *src, *fstype; int rc = 0; DBG(UPDATE, ul_debug("setting FS root")); @@ -366,16 +366,21 @@ static int set_fs_root(struct libmnt_update *upd, struct libmnt_fs *fs, assert(upd->fs); assert(fs); + fstype = mnt_fs_get_fstype(fs); + if (mountflags & MS_BIND) { if (!upd->mountinfo) upd->mountinfo = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO); - src = mnt_fs_get_srcpath(fs); if (src) { rc = mnt_fs_set_bindsrc(upd->fs, src); if (rc) goto err; } + + } else if (fstype && (strcmp(fstype, "btrfs") == 0 || strcmp(fstype, "auto") == 0)) { + if (!upd->mountinfo) + upd->mountinfo = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO); } src_fs = mnt_table_get_fs_root(upd->mountinfo, fs, -- cgit v1.2.3-55-g7522