diff options
author | Greg Kurz <groug@kaod.org> | 2017-02-26 23:42:51 +0100 |
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committer | Greg Kurz <groug@kaod.org> | 2017-02-28 11:21:15 +0100 |
commit | 72f0d0bf51362011c4d841a89fb8f5cfb16e0bf3 (patch) | |
tree | f331ff1b1b177f6273edb2f989c3f95159c41e39 /hw/9pfs/9p-xattr-user.c | |
parent | 3e36aba757f76673007a80b3cd56a4062c2e3462 (diff) |
9pfs: local: lremovexattr: don't follow symlinks
The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.
This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().
local_lremovexattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw/9pfs/9p-xattr-user.c')
-rw-r--r-- | hw/9pfs/9p-xattr-user.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c index 1840a5db66..2c90817b75 100644 --- a/hw/9pfs/9p-xattr-user.c +++ b/hw/9pfs/9p-xattr-user.c @@ -81,9 +81,6 @@ static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name, static int mp_user_removexattr(FsContext *ctx, const char *path, const char *name) { - char *buffer; - int ret; - if (strncmp(name, "user.virtfs.", 12) == 0) { /* * Don't allow fetch of user.virtfs namesapce @@ -92,10 +89,7 @@ static int mp_user_removexattr(FsContext *ctx, errno = EACCES; return -1; } - buffer = rpath(ctx, path); - ret = lremovexattr(buffer, name); - g_free(buffer); - return ret; + return local_removexattr_nofollow(ctx, path, name); } XattrOperations mapped_user_xattr = { |