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kernel/0001-xfs-More-robust-inode-extent-count-validation.patch
Jeremy Cline c50701879a
Fix for CVE-2018-13095 depends on 7d71a671a2d9 
The build 4.17.5 build failed because "fa" was not declared.

Signed-off-by: Jeremy Cline <jcline@redhat.com>
2018-07-09 12:42:46 -04:00

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From 7d71a671a2d900606d3a62ed5976d3b0feada3a6 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 5 Jun 2018 10:06:44 -0700
Subject: [PATCH] xfs: verify extent size hint is valid in inode verifier
There are rules for vald extent size hints. We enforce them when
applications set them, but fuzzers violate those rules and that
screws us over.
This results in alignment assertion failures when setting up
allocations such as this in direct IO:
XFS: Assertion failed: ap->length, file: fs/xfs/libxfs/xfs_bmap.c, line: 3432
....
Call Trace:
xfs_bmap_btalloc+0x415/0x910
xfs_bmapi_write+0x71c/0x12e0
xfs_iomap_write_direct+0x2a9/0x420
xfs_file_iomap_begin+0x4dc/0xa70
iomap_apply+0x43/0x100
iomap_file_buffered_write+0x62/0x90
xfs_file_buffered_aio_write+0xba/0x300
__vfs_write+0xd5/0x150
vfs_write+0xb6/0x180
ksys_write+0x45/0xa0
do_syscall_64+0x5a/0x180
entry_SYSCALL_64_after_hwframe+0x49/0xbe
And from xfs_db:
core.extsize = 10380288
Which is not an integer multiple of the block size, and so violates
Rule #7 for setting extent size hints. Validate extent size hint
rules in the inode verifier to catch this.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jeremy Cline <jcline@redhat.com>
---
fs/xfs/libxfs/xfs_inode_buf.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 1201107eabc6..1fe18555b451 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -397,6 +397,7 @@ xfs_dinode_verify(
xfs_ino_t ino,
struct xfs_dinode *dip)
{
+ xfs_failaddr_t fa;
uint16_t mode;
uint16_t flags;
uint64_t flags2;
@@ -513,6 +514,12 @@ xfs_dinode_verify(
return __this_address;
}
+ /* extent size hint validation */
+ fa = xfs_inode_validate_extsize(mp, be32_to_cpu(dip->di_extsize),
+ mode, flags);
+ if (fa)
+ return fa;
+
/* only version 3 or greater inodes are extensively verified here */
if (dip->di_version < 3)
return NULL;
@@ -521,7 +528,7 @@ xfs_dinode_verify(
/* don't allow reflink/cowextsize if we don't have reflink */
if ((flags2 & (XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE)) &&
- !xfs_sb_version_hasreflink(&mp->m_sb))
+ !xfs_sb_version_hasreflink(&mp->m_sb))
return __this_address;
/* only regular files get reflink */
--
2.17.1
From 23fcb3340d033d9f081e21e6c12c2db7eaa541d3 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Thu, 21 Jun 2018 23:25:57 -0700
Subject: [PATCH] xfs: More robust inode extent count validation
When the inode is in extent format, it can't have more extents that
fit in the inode fork. We don't currenty check this, and so this
corruption goes unnoticed by the inode verifiers. This can lead to
crashes operating on invalid in-memory structures.
Attempts to access such a inode will now error out in the verifier
rather than allowing modification operations to proceed.
Reported-by: Wen Xu <wen.xu@gatech.edu>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: fix a typedef, add some braces and breaks to shut up compiler warnings]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_format.h | 3 ++
fs/xfs/libxfs/xfs_inode_buf.c | 76 ++++++++++++++++++++++-------------
2 files changed, 50 insertions(+), 29 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 1c5a8aaf2bfc..7b4a43deb83e 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -962,6 +962,9 @@ typedef enum xfs_dinode_fmt {
XFS_DFORK_DSIZE(dip, mp) : \
XFS_DFORK_ASIZE(dip, mp))
+#define XFS_DFORK_MAXEXT(dip, mp, w) \
+ (XFS_DFORK_SIZE(dip, mp, w) / sizeof(struct xfs_bmbt_rec))
+
/*
* Return pointers to the data or attribute forks.
*/
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index d38d724534c4..33dc34655ac3 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -374,6 +374,47 @@ xfs_log_dinode_to_disk(
}
}
+static xfs_failaddr_t
+xfs_dinode_verify_fork(
+ struct xfs_dinode *dip,
+ struct xfs_mount *mp,
+ int whichfork)
+{
+ uint32_t di_nextents = XFS_DFORK_NEXTENTS(dip, whichfork);
+
+ switch (XFS_DFORK_FORMAT(dip, whichfork)) {
+ case XFS_DINODE_FMT_LOCAL:
+ /*
+ * no local regular files yet
+ */
+ if (whichfork == XFS_DATA_FORK) {
+ if (S_ISREG(be16_to_cpu(dip->di_mode)))
+ return __this_address;
+ if (be64_to_cpu(dip->di_size) >
+ XFS_DFORK_SIZE(dip, mp, whichfork))
+ return __this_address;
+ }
+ if (di_nextents)
+ return __this_address;
+ break;
+ case XFS_DINODE_FMT_EXTENTS:
+ if (di_nextents > XFS_DFORK_MAXEXT(dip, mp, whichfork))
+ return __this_address;
+ break;
+ case XFS_DINODE_FMT_BTREE:
+ if (whichfork == XFS_ATTR_FORK) {
+ if (di_nextents > MAXAEXTNUM)
+ return __this_address;
+ } else if (di_nextents > MAXEXTNUM) {
+ return __this_address;
+ }
+ break;
+ default:
+ return __this_address;
+ }
+ return NULL;
+}
+
xfs_failaddr_t
xfs_dinode_verify(
struct xfs_mount *mp,
@@ -441,24 +482,9 @@ xfs_dinode_verify(
case S_IFREG:
case S_IFLNK:
case S_IFDIR:
- switch (dip->di_format) {
- case XFS_DINODE_FMT_LOCAL:
- /*
- * no local regular files yet
- */
- if (S_ISREG(mode))
- return __this_address;
- if (di_size > XFS_DFORK_DSIZE(dip, mp))
- return __this_address;
- if (dip->di_nextents)
- return __this_address;
- /* fall through */
- case XFS_DINODE_FMT_EXTENTS:
- case XFS_DINODE_FMT_BTREE:
- break;
- default:
- return __this_address;
- }
+ fa = xfs_dinode_verify_fork(dip, mp, XFS_DATA_FORK);
+ if (fa)
+ return fa;
break;
case 0:
/* Uninitialized inode ok. */
@@ -468,17 +494,9 @@ xfs_dinode_verify(
}
if (XFS_DFORK_Q(dip)) {
- switch (dip->di_aformat) {
- case XFS_DINODE_FMT_LOCAL:
- if (dip->di_anextents)
- return __this_address;
- /* fall through */
- case XFS_DINODE_FMT_EXTENTS:
- case XFS_DINODE_FMT_BTREE:
- break;
- default:
- return __this_address;
- }
+ fa = xfs_dinode_verify_fork(dip, mp, XFS_ATTR_FORK);
+ if (fa)
+ return fa;
} else {
/*
* If there is no fork offset, this may be a freshly-made inode
--
2.17.1
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