[PATCH 4.4-cip 21/23] xfs: fix signed integer overflow


Ben Hutchings <ben.hutchings@...>
 

From: Xie XiuQi <xiexiuqi@...>

commit 79c350e45ebc5a718cc2d7114b45ad560069423d upstream.

Use 1U for unsigned int to avoid a overflow warning from UBSAN.

[ 31.910858] UBSAN: Undefined behaviour in fs/xfs/xfs_buf_item.c:889:25
[ 31.911252] signed integer overflow:
[ 31.911478] -2147483648 - 1 cannot be represented in type 'int'
[ 31.911846] CPU: 1 PID: 1011 Comm: tuned Tainted: G B ---- ------- 3.10.0-327.28.3.el7.x86_64 #1
[ 31.911857] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 01/07/2011
[ 31.911866] 1ffff1004069cd3b 0000000076bec3fd ffff8802034e69a0 ffffffff81ee3140
[ 31.911883] ffff8802034e69b8 ffffffff81ee31fd ffffffffa0ad79e0 ffff8802034e6b20
[ 31.911898] ffffffff81ee46e2 0000002d515470c0 0000000000000001 0000000041b58ab3
[ 31.911913] Call Trace:
[ 31.911932] [<ffffffff81ee3140>] dump_stack+0x1e/0x20
[ 31.911947] [<ffffffff81ee31fd>] ubsan_epilogue+0x12/0x55
[ 31.911964] [<ffffffff81ee46e2>] handle_overflow+0x1ba/0x215
[ 31.912083] [<ffffffff81ee4798>] __ubsan_handle_sub_overflow+0x2a/0x31
[ 31.912204] [<ffffffffa08676fb>] xfs_buf_item_log+0x34b/0x3f0 [xfs]
[ 31.912314] [<ffffffffa0880490>] xfs_trans_log_buf+0x120/0x260 [xfs]
[ 31.912402] [<ffffffffa079a890>] xfs_btree_log_recs+0x80/0xc0 [xfs]
[ 31.912490] [<ffffffffa07a29f8>] xfs_btree_delrec+0x11a8/0x2d50 [xfs]
[ 31.913589] [<ffffffffa07a86f9>] xfs_btree_delete+0xc9/0x260 [xfs]
[ 31.913762] [<ffffffffa075b5cf>] xfs_free_ag_extent+0x63f/0xe20 [xfs]
[ 31.914339] [<ffffffffa075ec0f>] xfs_free_extent+0x2af/0x3e0 [xfs]
[ 31.914641] [<ffffffffa0801b2b>] xfs_bmap_finish+0x32b/0x4b0 [xfs]
[ 31.914841] [<ffffffffa083c2e7>] xfs_itruncate_extents+0x3b7/0x740 [xfs]
[ 31.915216] [<ffffffffa08342fa>] xfs_setattr_size+0x60a/0x860 [xfs]
[ 31.915471] [<ffffffffa08345ea>] xfs_vn_setattr+0x9a/0xe0 [xfs]
[ 31.915590] [<ffffffff8149ad38>] notify_change+0x5c8/0x8a0
[ 31.915607] [<ffffffff81450f22>] do_truncate+0x122/0x1d0
[ 31.915640] [<ffffffff8147beee>] do_last+0x15de/0x2c80
[ 31.915707] [<ffffffff8147d777>] path_openat+0x1e7/0xcc0
[ 31.915802] [<ffffffff81480824>] do_filp_open+0xa4/0x160
[ 31.915848] [<ffffffff81453127>] do_sys_open+0x1b7/0x3f0
[ 31.915879] [<ffffffff81453392>] SyS_open+0x32/0x40
[ 31.915897] [<ffffffff81f08989>] system_call_fastpath+0x16/0x1b

[ 240.086809] UBSAN: Undefined behaviour in fs/xfs/xfs_buf_item.c:866:34
[ 240.086820] signed integer overflow:
[ 240.086830] -2147483648 - 1 cannot be represented in type 'int'
[ 240.086846] CPU: 1 PID: 12969 Comm: rm Tainted: G B ---- ------- 3.10.0-327.28.3.el7.x86_64 #1
[ 240.086857] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 01/07/2011
[ 240.086868] 1ffff10040491def 00000000e2ea59c1 ffff88020248ef40 ffffffff81ee3140
[ 240.086885] ffff88020248ef58 ffffffff81ee31fd ffffffffa0ad79e0 ffff88020248f0c0
[ 240.086901] ffffffff81ee46e2 0000002d02488000 0000000000000001 0000000041b58ab3
[ 240.086915] Call Trace:
[ 240.086938] [<ffffffff81ee3140>] dump_stack+0x1e/0x20
[ 240.086953] [<ffffffff81ee31fd>] ubsan_epilogue+0x12/0x55
[ 240.086971] [<ffffffff81ee46e2>] handle_overflow+0x1ba/0x215
...

Signed-off-by: Xie XiuQi <xiexiuqi@...>
Reviewed-by: Dave Chinner <dchinner@...>
Signed-off-by: Dave Chinner <david@...>
Signed-off-by: Ben Hutchings <ben.hutchings@...>
---
fs/xfs/xfs_buf_item.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 7e986da34f6c..04b1d96e49c1 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -865,7 +865,7 @@ xfs_buf_item_log_segment(
*/
if (bit) {
end_bit = MIN(bit + bits_to_set, (uint)NBWORD);
- mask = ((1 << (end_bit - bit)) - 1) << bit;
+ mask = ((1U << (end_bit - bit)) - 1) << bit;
*wordp |= mask;
wordp++;
bits_set = end_bit - bit;
@@ -888,7 +888,7 @@ xfs_buf_item_log_segment(
*/
end_bit = bits_to_set - bits_set;
if (end_bit) {
- mask = (1 << end_bit) - 1;
+ mask = (1U << end_bit) - 1;
*wordp |= mask;
}
}
--
2.10.2



--
Ben Hutchings
Software Developer, Codethink Ltd.

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