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authorAl Viro <viro@zeniv.linux.org.uk>2023-03-06 01:20:30 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-04-05 11:16:40 +0200
commit299a309b98df4e349acaffca23cff72105f1c0a5 (patch)
tree0c58a2658d94b38ef32adbc9601dfd20ea01d919 /arch/sh
parentf4c610f6ca1303dcc896a12c85a15b787731739e (diff)
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sh: sanitize the flags on sigreturn
[ Upstream commit 573b22ccb7ce9ab7f0539a2e11a9d3609a8783f5 ] We fetch %SR value from sigframe; it might have been modified by signal handler, so we can't trust it with any bits that are not modifiable in user mode. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Rich Felker <dalias@libc.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/include/asm/processor_32.h1
-rw-r--r--arch/sh/kernel/signal_32.c3
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 0e0ecc0132e3..58ae979798fa 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -51,6 +51,7 @@
#define SR_FD 0x00008000
#define SR_MD 0x40000000
+#define SR_USER_MASK 0x00000303 // M, Q, S, T bits
/*
* DSP structure and data
*/
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index 24473fa6c3b6..f6e1a47ad7ca 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -116,6 +116,7 @@ static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
{
unsigned int err = 0;
+ unsigned int sr = regs->sr & ~SR_USER_MASK;
#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
COPY(regs[1]);
@@ -131,6 +132,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p
COPY(sr); COPY(pc);
#undef COPY
+ regs->sr = (regs->sr & SR_USER_MASK) | sr;
+
#ifdef CONFIG_SH_FPU
if (boot_cpu_data.flags & CPU_HAS_FPU) {
int owned_fp;