diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2014-10-27 08:28:08 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-10-27 13:27:02 +0100 |
| commit | 9b2efe035eafb1a29ff3dfe21ed0e755aac09130 (patch) | |
| tree | 37f0a0c357aaf7305ca9acf2850c78da576c4f93 /arch/s390/kernel/vdso32 | |
| parent | s390/time: use stck clock fast for do_account_vtime (diff) | |
| download | linux-9b2efe035eafb1a29ff3dfe21ed0e755aac09130.tar.xz linux-9b2efe035eafb1a29ff3dfe21ed0e755aac09130.zip | |
s390/vdso: fix stack corruption
The kernel provided vdso functions do not get a stack frame from the
calling function and therefore may not change the stack contents, unless
they allocate space on their own.
This problem was exposed with 070b7be633dc "s390/vdso: replace stck with
stcke" which writes 16 bytes instead of 8 bytes into the stack frame. These
additional 8 bytes however were indeed used by the caller (glibc) to save
data and therefore this data was corrupted by the vdso code.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/vdso32')
| -rw-r--r-- | arch/s390/kernel/vdso32/clock_gettime.S | 12 | ||||
| -rw-r--r-- | arch/s390/kernel/vdso32/gettimeofday.S | 14 |
2 files changed, 16 insertions, 10 deletions
diff --git a/arch/s390/kernel/vdso32/clock_gettime.S b/arch/s390/kernel/vdso32/clock_gettime.S index 48c2206a3956..5eec9afbb5b5 100644 --- a/arch/s390/kernel/vdso32/clock_gettime.S +++ b/arch/s390/kernel/vdso32/clock_gettime.S @@ -19,6 +19,7 @@ .type __kernel_clock_gettime,@function __kernel_clock_gettime: .cfi_startproc + ahi %r15,-16 basr %r5,0 0: al %r5,21f-0b(%r5) /* get &_vdso_data */ chi %r2,__CLOCK_REALTIME_COARSE @@ -34,8 +35,8 @@ __kernel_clock_gettime: 1: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 1b - stcke 24(%r15) /* Store TOD clock */ - lm %r0,%r1,25(%r15) + stcke 0(%r15) /* Store TOD clock */ + lm %r0,%r1,1(%r15) s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,2f @@ -70,6 +71,7 @@ __kernel_clock_gettime: 8: st %r2,0(%r3) /* store tp->tv_sec */ st %r1,4(%r3) /* store tp->tv_nsec */ lhi %r2,0 + ahi %r15,16 br %r14 /* CLOCK_MONOTONIC_COARSE */ @@ -96,8 +98,8 @@ __kernel_clock_gettime: 11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 11b - stcke 24(%r15) /* Store TOD clock */ - lm %r0,%r1,25(%r15) + stcke 0(%r15) /* Store TOD clock */ + lm %r0,%r1,1(%r15) s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,12f @@ -132,11 +134,13 @@ __kernel_clock_gettime: 17: st %r2,0(%r3) /* store tp->tv_sec */ st %r1,4(%r3) /* store tp->tv_nsec */ lhi %r2,0 + ahi %r15,16 br %r14 /* Fallback to system call */ 19: lhi %r1,__NR_clock_gettime svc 0 + ahi %r15,16 br %r14 20: .long 1000000000 diff --git a/arch/s390/kernel/vdso32/gettimeofday.S b/arch/s390/kernel/vdso32/gettimeofday.S index 60def5f562db..719de6186b20 100644 --- a/arch/s390/kernel/vdso32/gettimeofday.S +++ b/arch/s390/kernel/vdso32/gettimeofday.S @@ -19,6 +19,7 @@ .type __kernel_gettimeofday,@function __kernel_gettimeofday: .cfi_startproc + ahi %r15,-16 basr %r5,0 0: al %r5,13f-0b(%r5) /* get &_vdso_data */ 1: ltr %r3,%r3 /* check if tz is NULL */ @@ -29,30 +30,30 @@ __kernel_gettimeofday: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 1b - stcke 24(%r15) /* Store TOD clock */ - lm %r0,%r1,25(%r15) + stcke 0(%r15) /* Store TOD clock */ + lm %r0,%r1,1(%r15) s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,3f ahi %r0,-1 3: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */ - st %r0,24(%r15) + st %r0,0(%r15) l %r0,__VDSO_TK_MULT(%r5) ltr %r1,%r1 mr %r0,%r0 jnm 4f a %r0,__VDSO_TK_MULT(%r5) -4: al %r0,24(%r15) +4: al %r0,0(%r15) al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */ al %r1,__VDSO_XTIME_NSEC+4(%r5) brc 12,5f ahi %r0,1 -5: mvc 24(4,%r15),__VDSO_XTIME_SEC+4(%r5) +5: mvc 0(4,%r15),__VDSO_XTIME_SEC+4(%r5) cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */ jne 1b l %r4,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ srdl %r0,0(%r4) /* >> tk->shift */ - l %r4,24(%r15) /* get tv_sec from stack */ + l %r4,0(%r15) /* get tv_sec from stack */ basr %r5,0 6: ltr %r0,%r0 jnz 7f @@ -71,6 +72,7 @@ __kernel_gettimeofday: 9: srl %r0,6 st %r0,4(%r2) /* store tv->tv_usec */ 10: slr %r2,%r2 + ahi %r15,16 br %r14 11: .long 1000000000 12: .long 274877907 |