Patchwork libext2fs: only use override function when reading an 128 byte inode

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Submitter Theodore Ts'o
Date April 22, 2013, 3:56 a.m.
Message ID <1366602969-26187-1-git-send-email-tytso@mit.edu>
Download mbox | patch
Permalink /patch/238312/
State Accepted
Headers show

Comments

Theodore Ts'o - April 22, 2013, 3:56 a.m.
The ext2fs_read_inode_full() function should not use fs->read_inode()
if the caller has requested more than the base 128 byte inode
structure and the inode size is greater than 128 bytes.  Otherwise the
caller won't get all of the bytes that they were asking for, since
there's no way for the fs->read_inode override function can know what
the size of the buffer passed to ext2fs_read_inode_full().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 lib/ext2fs/inode.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
Carlos Maiolino - April 22, 2013, 3:11 p.m.
Looks Good,

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

On Sun, Apr 21, 2013 at 11:56:09PM -0400, Theodore Ts'o wrote:
> The ext2fs_read_inode_full() function should not use fs->read_inode()
> if the caller has requested more than the base 128 byte inode
> structure and the inode size is greater than 128 bytes.  Otherwise the
> caller won't get all of the bytes that they were asking for, since
> there's no way for the fs->read_inode override function can know what
> the size of the buffer passed to ext2fs_read_inode_full().
> 
> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
> ---
>  lib/ext2fs/inode.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
> index 77fc447..fd72d4c 100644
> --- a/lib/ext2fs/inode.c
> +++ b/lib/ext2fs/inode.c
> @@ -533,7 +533,9 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
>  	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
>  
>  	/* Check to see if user has an override function */
> -	if (fs->read_inode) {
> +	if (fs->read_inode &&
> +	    ((bufsize == sizeof(struct ext2_inode)) ||
> +	     (EXT2_INODE_SIZE(fs->super) == sizeof(struct ext2_inode)))) {
>  		retval = (fs->read_inode)(fs, ino, inode);
>  		if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
>  			return retval;
> -- 
> 1.7.12.rc0.22.gcdd159b
> 
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Patch

diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
index 77fc447..fd72d4c 100644
--- a/lib/ext2fs/inode.c
+++ b/lib/ext2fs/inode.c
@@ -533,7 +533,9 @@  errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 
 	/* Check to see if user has an override function */
-	if (fs->read_inode) {
+	if (fs->read_inode &&
+	    ((bufsize == sizeof(struct ext2_inode)) ||
+	     (EXT2_INODE_SIZE(fs->super) == sizeof(struct ext2_inode)))) {
 		retval = (fs->read_inode)(fs, ino, inode);
 		if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 			return retval;