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sparc: Harden signal return frame checks.

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All signal frames must be at least 16-byte aligned, because that is
the alignment we explicitly create when we build signal return stack
frames.

All stack pointers must be at least 8-byte aligned.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2016-05-28 21:21:31 -07:00
parent 9ea46abe22
commit d11c2a0de2
5 changed files with 92 additions and 45 deletions
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46
arch/sparc/kernel/signal32.c
View File

@ -138,12 +138,24 @@ int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
return 0;
}
/* Checks if the fp is valid. We always build signal frames which are
* 16-byte aligned, therefore we can always enforce that the restore
* frame has that property as well.
*/
static bool invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 15) ||
((unsigned long)fp) > 0x100000000ULL - fplen)
return true;
return false;
}
void do_sigreturn32(struct pt_regs *regs)
{
struct signal_frame32 __user *sf;
compat_uptr_t fpu_save;
compat_uptr_t rwin_save;
unsigned int psr;
unsigned int psr, ufp;
unsigned int pc, npc;
sigset_t set;
compat_sigset_t seta;
@ -158,11 +170,16 @@ void do_sigreturn32(struct pt_regs *regs)
sf = (struct signal_frame32 __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
(((unsigned long) sf) & 3))
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(pc, &sf->info.si_regs.pc) ||
if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
if (__get_user(pc, &sf->info.si_regs.pc) ||
__get_user(npc, &sf->info.si_regs.npc))
goto segv;
@ -227,7 +244,7 @@ segv:
asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
{
struct rt_signal_frame32 __user *sf;
unsigned int psr, pc, npc;
unsigned int psr, pc, npc, ufp;
compat_uptr_t fpu_save;
compat_uptr_t rwin_save;
sigset_t set;
@ -242,11 +259,16 @@ asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
sf = (struct rt_signal_frame32 __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
(((unsigned long) sf) & 3))
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(pc, &sf->regs.pc) ||
if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
if (__get_user(pc, &sf->regs.pc) ||
__get_user(npc, &sf->regs.npc))
goto segv;
@ -307,14 +329,6 @@ segv:
force_sig(SIGSEGV, current);
}
/* Checks if the fp is valid */
static int invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 7) || ((unsigned long)fp) > 0x100000000ULL - fplen)
return 1;
return 0;
}
static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp;

41
arch/sparc/kernel/signal_32.c
View File

@ -60,10 +60,22 @@ struct rt_signal_frame {
#define SF_ALIGNEDSZ (((sizeof(struct signal_frame) + 7) & (~7)))
#define RT_ALIGNEDSZ (((sizeof(struct rt_signal_frame) + 7) & (~7)))
/* Checks if the fp is valid. We always build signal frames which are
* 16-byte aligned, therefore we can always enforce that the restore
* frame has that property as well.
*/
static inline bool invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 15) || !__access_ok((unsigned long)fp, fplen))
return true;
return false;
}
asmlinkage void do_sigreturn(struct pt_regs *regs)
{
unsigned long up_psr, pc, npc, ufp;
struct signal_frame __user *sf;
unsigned long up_psr, pc, npc;
sigset_t set;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
@ -77,10 +89,13 @@ asmlinkage void do_sigreturn(struct pt_regs *regs)
sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
if (!invalid_frame_pointer(sf, sizeof(*sf)))
goto segv_and_exit;
if (((unsigned long) sf) & 3)
if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
goto segv_and_exit;
if (ufp & 0x7)
goto segv_and_exit;
err = __get_user(pc, &sf->info.si_regs.pc);
@ -127,7 +142,7 @@ segv_and_exit:
asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
{
struct rt_signal_frame __user *sf;
unsigned int psr, pc, npc;
unsigned int psr, pc, npc, ufp;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
sigset_t set;
@ -135,8 +150,13 @@ asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
synchronize_user_stack();
sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP];
if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
(((unsigned long) sf) & 0x03))
if (!invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
err = __get_user(pc, &sf->regs.pc);
@ -178,15 +198,6 @@ segv:
force_sig(SIGSEGV, current);
}
/* Checks if the fp is valid */
static inline int invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 7) || !__access_ok((unsigned long)fp, fplen))
return 1;
return 0;
}
static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp = regs->u_regs[UREG_FP];

31
arch/sparc/kernel/signal_64.c
View File

@ -234,6 +234,17 @@ do_sigsegv:
goto out;
}
/* Checks if the fp is valid. We always build rt signal frames which
* are 16-byte aligned, therefore we can always enforce that the
* restore frame has that property as well.
*/
static bool invalid_frame_pointer(void __user *fp)
{
if (((unsigned long) fp) & 15)
return true;
return false;
}
struct rt_signal_frame {
struct sparc_stackf ss;
siginfo_t info;
@ -246,8 +257,8 @@ struct rt_signal_frame {
void do_rt_sigreturn(struct pt_regs *regs)
{
unsigned long tpc, tnpc, tstate, ufp;
struct rt_signal_frame __user *sf;
unsigned long tpc, tnpc, tstate;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
sigset_t set;
@ -261,10 +272,16 @@ void do_rt_sigreturn(struct pt_regs *regs)
(regs->u_regs [UREG_FP] + STACK_BIAS);
/* 1. Make sure we are not getting garbage from the user */
if (((unsigned long) sf) & 3)
if (invalid_frame_pointer(sf))
goto segv;
err = get_user(tpc, &sf->regs.tpc);
if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
if ((ufp + STACK_BIAS) & 0x7)
goto segv;
err = __get_user(tpc, &sf->regs.tpc);
err |= __get_user(tnpc, &sf->regs.tnpc);
if (test_thread_flag(TIF_32BIT)) {
tpc &= 0xffffffff;
@ -308,14 +325,6 @@ segv:
force_sig(SIGSEGV, current);
}
/* Checks if the fp is valid */
static int invalid_frame_pointer(void __user *fp)
{
if (((unsigned long) fp) & 15)
return 1;
return 0;
}
static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;

9
arch/sparc/kernel/sigutil_32.c
View File

@ -48,6 +48,10 @@ int save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
int restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
{
int err;
if (((unsigned long) fpu) & 3)
return -EFAULT;
#ifdef CONFIG_SMP
if (test_tsk_thread_flag(current, TIF_USEDFPU))
regs->psr &= ~PSR_EF;
@ -97,7 +101,10 @@ int restore_rwin_state(__siginfo_rwin_t __user *rp)
struct thread_info *t = current_thread_info();
int i, wsaved, err;
__get_user(wsaved, &rp->wsaved);
if (((unsigned long) rp) & 3)
return -EFAULT;
get_user(wsaved, &rp->wsaved);
if (wsaved > NSWINS)
return -EFAULT;

10
arch/sparc/kernel/sigutil_64.c
View File

@ -37,7 +37,10 @@ int restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
unsigned long fprs;
int err;
err = __get_user(fprs, &fpu->si_fprs);
if (((unsigned long) fpu) & 7)
return -EFAULT;
err = get_user(fprs, &fpu->si_fprs);
fprs_write(0);
regs->tstate &= ~TSTATE_PEF;
if (fprs & FPRS_DL)
@ -72,7 +75,10 @@ int restore_rwin_state(__siginfo_rwin_t __user *rp)
struct thread_info *t = current_thread_info();
int i, wsaved, err;
__get_user(wsaved, &rp->wsaved);
if (((unsigned long) rp) & 7)
return -EFAULT;
get_user(wsaved, &rp->wsaved);
if (wsaved > NSWINS)
return -EFAULT;