Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 19/21] s390/ptrace: fix PSW mask check | Date | Tue, 29 Jul 2014 18:48:48 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Martin Schwidefsky <schwidefsky@de.ibm.com>
commit dab6cf55f81a6e16b8147aed9a843e1691dcd318 upstream.
The PSW mask check of the PTRACE_POKEUSR_AREA command is incorrect. The PSW_MASK_USER define contains the PSW_MASK_ASC bits, the ptrace interface accepts all combinations for the address-space-control bits. To protect the kernel space the PSW mask check in ptrace needs to reject the address-space-control bit combination for home space.
Fixes CVE-2014-3534
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/s390/kernel/ptrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -314,7 +314,9 @@ static int __poke_user(struct task_struc * 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; @@ -627,7 +629,10 @@ static int __poke_user_compat(struct tas */ 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) |
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