4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jaegeuk Kim jaegeuk@kernel.org
commit 64beba0558fce7b59e9a8a7afd77290e82a22163 upstream.
There is a security report where f2fs_getxattr() has a hole to expose wrong memory region when the image is malformed like this.
f2fs_getxattr: entry->e_name_len: 4, size: 12288, buffer_size: 16384, len: 4
Cc: stable@vger.kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/f2fs/xattr.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
--- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -288,7 +288,7 @@ static int read_xattr_block(struct inode static int lookup_all_xattrs(struct inode *inode, struct page *ipage, unsigned int index, unsigned int len, const char *name, struct f2fs_xattr_entry **xe, - void **base_addr) + void **base_addr, int *base_size) { void *cur_addr, *txattr_addr, *last_addr = NULL; nid_t xnid = F2FS_I(inode)->i_xattr_nid; @@ -299,8 +299,8 @@ static int lookup_all_xattrs(struct inod if (!size && !inline_size) return -ENODATA;
- txattr_addr = f2fs_kzalloc(F2FS_I_SB(inode), - inline_size + size + XATTR_PADDING_SIZE, GFP_NOFS); + *base_size = inline_size + size + XATTR_PADDING_SIZE; + txattr_addr = f2fs_kzalloc(F2FS_I_SB(inode), *base_size, GFP_NOFS); if (!txattr_addr) return -ENOMEM;
@@ -312,8 +312,10 @@ static int lookup_all_xattrs(struct inod
*xe = __find_inline_xattr(inode, txattr_addr, &last_addr, index, len, name); - if (*xe) + if (*xe) { + *base_size = inline_size; goto check; + } }
/* read from xattr node block */ @@ -474,6 +476,7 @@ int f2fs_getxattr(struct inode *inode, i int error = 0; unsigned int size, len; void *base_addr = NULL; + int base_size;
if (name == NULL) return -EINVAL; @@ -484,7 +487,7 @@ int f2fs_getxattr(struct inode *inode, i
down_read(&F2FS_I(inode)->i_xattr_sem); error = lookup_all_xattrs(inode, ipage, index, len, name, - &entry, &base_addr); + &entry, &base_addr, &base_size); up_read(&F2FS_I(inode)->i_xattr_sem); if (error) return error; @@ -498,6 +501,11 @@ int f2fs_getxattr(struct inode *inode, i
if (buffer) { char *pval = entry->e_name + entry->e_name_len; + + if (base_size - (pval - (char *)base_addr) < size) { + error = -ERANGE; + goto out; + } memcpy(buffer, pval, size); } error = size;