[PATCH] check put_user fail in do_signal when enable OABI_COMPACT
From: Janboe Ye <hidden>
Date: 2009-10-21 11:07:57
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
Using OABI, do_signal need to copy restart_syscall to user stack. It is possible that put_user fail. This triggers flush_icache page fault and crash kernel. Signed-off-by: janboe <redacted> --- arch/arm/kernel/signal.c | 21 +++++++++++++-------- 1 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index f6bc5d4..2122d43 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c@@ -626,6 +626,7 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) struct k_sigaction ka; siginfo_t info; int signr; + int ret = 0; /* * We want the common case to go fast, which
@@ -679,16 +680,20 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) */ swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE; - put_user(regs->ARM_pc, &usp[0]); + ret |= put_user(regs->ARM_pc, &usp[0]); /* swi __NR_restart_syscall */ - put_user(0xef000000 | swival, &usp[1]); + ret |= put_user(0xef000000 | swival, &usp[1]); /* ldr pc, [sp], #12 */ - put_user(0xe49df00c, &usp[2]); - - flush_icache_range((unsigned long)usp, - (unsigned long)(usp + 3)); - - regs->ARM_pc = regs->ARM_sp + 4; + ret |= put_user(0xe49df00c, &usp[2]); + if (!ret) { + flush_icache_range((unsigned long)usp, + (unsigned long)(usp + 3)); + + regs->ARM_pc = regs->ARM_sp + 4; + } else { + regs->ARM_sp += 12; + force_sigsegv(0, current); + } #endif } }
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1.6.3.3