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| 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/vdso64/gettimeofday.S | |
| 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/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/gettimeofday.S | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/s390/kernel/vdso64/gettimeofday.S b/arch/s390/kernel/vdso64/gettimeofday.S index 7a344995a97f..6ce46707663c 100644 --- a/arch/s390/kernel/vdso64/gettimeofday.S +++ b/arch/s390/kernel/vdso64/gettimeofday.S @@ -19,6 +19,7 @@ .type __kernel_gettimeofday,@function __kernel_gettimeofday: .cfi_startproc + aghi %r15,-16 larl %r5,_vdso_data 0: ltgr %r3,%r3 /* check if tz is NULL */ je 1f @@ -28,8 +29,8 @@ __kernel_gettimeofday: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ tmll %r4,0x0001 /* pending update ? loop */ jnz 0b - stcke 48(%r15) /* Store TOD clock */ - lg %r1,49(%r15) + stcke 0(%r15) /* Store TOD clock */ + lg %r1,1(%r15) sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */ @@ -50,6 +51,7 @@ __kernel_gettimeofday: srlg %r0,%r0,6 stg %r0,8(%r2) /* store tv->tv_usec */ 4: lghi %r2,0 + aghi %r15,16 br %r14 5: .quad 1000000000 .long 274877907 |