The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch converts local_lgetxattr() to rely on opendir_nofollow() and
fgetxattrat_nofollow() instead.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
---
hw/9pfs/9p-posix-acl.c | 16 ++--------------
hw/9pfs/9p-xattr-user.c | 8 +-------
hw/9pfs/9p-xattr.c | 8 +-------
3 files changed, 4 insertions(+), 28 deletions(-)
diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
index ec003181cd33..9435e27a368c 100644
--- a/hw/9pfs/9p-posix-acl.c
+++ b/hw/9pfs/9p-posix-acl.c
@@ -25,13 +25,7 @@
static ssize_t mp_pacl_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
- char *buffer;
- ssize_t ret;
-
- buffer = rpath(ctx, path);
- ret = lgetxattr(buffer, MAP_ACL_ACCESS, value, size);
- g_free(buffer);
- return ret;
+ return local_getxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size);
}
static ssize_t mp_pacl_listxattr(FsContext *ctx, const char *path,
@@ -89,13 +83,7 @@ static int mp_pacl_removexattr(FsContext *ctx,
static ssize_t mp_dacl_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
- char *buffer;
- ssize_t ret;
-
- buffer = rpath(ctx, path);
- ret = lgetxattr(buffer, MAP_ACL_DEFAULT, value, size);
- g_free(buffer);
- return ret;
+ return local_getxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size);
}
static ssize_t mp_dacl_listxattr(FsContext *ctx, const char *path,
diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c
index f87530c8b526..4071fbc4c086 100644
--- a/hw/9pfs/9p-xattr-user.c
+++ b/hw/9pfs/9p-xattr-user.c
@@ -20,9 +20,6 @@
static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
- char *buffer;
- ssize_t ret;
-
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
@@ -31,10 +28,7 @@ static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
errno = ENOATTR;
return -1;
}
- buffer = rpath(ctx, path);
- ret = lgetxattr(buffer, name, value, size);
- g_free(buffer);
- return ret;
+ return local_getxattr_nofollow(ctx, path, name, value, size);
}
static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index 62993624ff64..4c3c0046bd47 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -304,13 +304,7 @@ int v9fs_remove_xattr(FsContext *ctx,
ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size)
{
- char *buffer;
- ssize_t ret;
-
- buffer = rpath(ctx, path);
- ret = lgetxattr(buffer, name, value, size);
- g_free(buffer);
- return ret;
+ return local_getxattr_nofollow(ctx, path, name, value, size);
}
int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,