diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-06-23 14:43:06 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-08-06 18:07:39 +0100 |
| commit | 438127dd5b66029f904e96900d0f90b1c5a80bf9 (patch) | |
| tree | b2919622291cd722a34c31adcb069089f81be0c8 | |
| parent | c4b4c3c5f8e6cbd1c0626a80b2ca8cd33aa0e50a (diff) | |
s390/ptrace: fix PSW mask check
commit dab6cf55f81a6e16b8147aed9a843e1691dcd318 upstream.
The PSW mask check of the PTRACE_POKEUSR_AREA command is incorrect.
For the default user_mode=home address space layout the psw_user_bits
variable has the home space address-space-control bits set. But the
PSW_MASK_USER contains PSW_MASK_ASC, the ptrace validity check for the
PSW mask will therefore always fail.
Fixes CVE-2014-3534
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/s390/kernel/ptrace.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index afe82bc7b92..b76230b6661 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -292,7 +292,9 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data) * psw and gprs are stored on the stack */ if (addr == (addr_t) &dummy->regs.psw.mask && - ((data & ~PSW_MASK_USER) != psw_user_bits || + (((data^psw_user_bits) & ~PSW_MASK_USER) || + (((data^psw_user_bits) & PSW_MASK_ASC) && + ((data|psw_user_bits) & PSW_MASK_ASC) == PSW_MASK_ASC) || ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA)))) /* Invalid psw mask. */ return -EINVAL; @@ -595,7 +597,10 @@ static int __poke_user_compat(struct task_struct *child, */ if (addr == (addr_t) &dummy32->regs.psw.mask) { /* Build a 64 bit psw mask from 31 bit mask. */ - if ((tmp & ~PSW32_MASK_USER) != psw32_user_bits) + if (((tmp^psw32_user_bits) & ~PSW32_MASK_USER) || + (((tmp^psw32_user_bits) & PSW32_MASK_ASC) && + ((tmp|psw32_user_bits) & PSW32_MASK_ASC) + == PSW32_MASK_ASC)) /* Invalid psw mask. */ return -EINVAL; regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) | |