sh: sanitize the flags on sigreturn

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>
This commit is contained in:
Al Viro 2023-03-06 01:20:30 +00:00 committed by Linus Torvalds
parent 6a98c9cae2
commit 573b22ccb7
2 changed files with 4 additions and 0 deletions

View File

@ -50,6 +50,7 @@
#define SR_FD 0x00008000
#define SR_MD 0x40000000
#define SR_USER_MASK 0x00000303 // M, Q, S, T bits
/*
* DSP structure and data
*/

View File

@ -115,6 +115,7 @@ 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]);
@ -130,6 +131,8 @@ 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;