Btrfs devel - May 2013 - [PATCH] btrfs: don't stop searching after encountering the wrong item

The search ioctl skips items that are too large for a result buffer, but
inline items of a certain size occuring before any search result is
found would trigger an overflow and stop the search entirely.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=57641

Signed-off-by: Gabriel de Perthuis <g2p.code+btrfs@gmail.com>
---
 fs/btrfs/ioctl.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 95d46cc..b3f0276 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1797,23 +1797,23 @@ static noinline int copy_to_sk(struct btrfs_root *root,
 
 	for (i = slot; i < nritems; i++) {
 		item_off = btrfs_item_ptr_offset(leaf, i);
 		item_len = btrfs_item_size_nr(leaf, i);
 
-		if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
+		btrfs_item_key_to_cpu(leaf, key, i);
+		if (!key_in_sk(key, sk))
+			continue;
+
+		if (sizeof(sh) + item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
 			item_len = 0;
 
 		if (sizeof(sh) + item_len + *sk_offset >
 		    BTRFS_SEARCH_ARGS_BUFSIZE) {
 			ret = 1;
 			goto overflow;
 		}
 
-		btrfs_item_key_to_cpu(leaf, key, i);
-		if (!key_in_sk(key, sk))
-			continue;
-
 		sh.objectid = key->objectid;
 		sh.offset = key->offset;
 		sh.type = key->type;
 		sh.len = item_len;
 		sh.transid = found_transid;
-- 
1.8.2.1.419.ga0b97c6

On Mon, May 06, 2013 at 07:40:18PM +0200, Gabriel de Perthuis
wrote:
> The search ioctl skips items that are too large for a result buffer, but
> inline items of a certain size occuring before any search result is
> found would trigger an overflow and stop the search entirely.
> 
> Bug: https://bugzilla.kernel.org/show_bug.cgi?id=57641
> 
> Signed-off-by: Gabriel de Perthuis <g2p.code+btrfs@gmail.com>
> ---
>  fs/btrfs/ioctl.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>

The search ioctl skips items that are too large for a result buffer, but
inline items of a certain size occuring before any search result is
found would trigger an overflow and stop the search entirely.

Cc: stable@vger.kernel.org
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=57641

Signed-off-by: Gabriel de Perthuis <g2p.code+btrfs@gmail.com>
---
(resent, with the correct header to have stable copied)

 fs/btrfs/ioctl.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2c02310..f49b62f 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1794,23 +1794,23 @@ static noinline int copy_to_sk(struct btrfs_root *root,
 
 	for (i = slot; i < nritems; i++) {
 		item_off = btrfs_item_ptr_offset(leaf, i);
 		item_len = btrfs_item_size_nr(leaf, i);
 
-		if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
+		btrfs_item_key_to_cpu(leaf, key, i);
+		if (!key_in_sk(key, sk))
+			continue;
+
+		if (sizeof(sh) + item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
 			item_len = 0;
 
 		if (sizeof(sh) + item_len + *sk_offset >
 		    BTRFS_SEARCH_ARGS_BUFSIZE) {
 			ret = 1;
 			goto overflow;
 		}
 
-		btrfs_item_key_to_cpu(leaf, key, i);
-		if (!key_in_sk(key, sk))
-			continue;
-
 		sh.objectid = key->objectid;
 		sh.offset = key->offset;
 		sh.type = key->type;
 		sh.len = item_len;
 		sh.transid = found_transid;
-- 
1.8.2.1.419.ga0b97c6

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