This is a note to let you know that I've just added the patch titled
sh: sanitize the flags on sigreturn
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sh-sanitize-the-flags-on-sigreturn.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ba9fd1765f01b7f4dae38058a52bcf7c53821aef
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Mon Mar 6 01:20:30 2023 +0000
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@xxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 0e0ecc0132e3b..58ae979798fa8 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 24473fa6c3b63..f6e1a47ad7ca0 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;
