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parisc: compat Fix siginfo_t -> compat_siginfo_t conversion on big endian

PATCH In review Helge Deller 2 participants 2 messages Mar 15, 2015 – Mar 17, 2015 PA-RISC architecture

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Helge Deller

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#0 lore raw

PATCH 1/1 parisc: compat Fix siginfo_t -> compat_siginfo_t conversion on big endian

This patch is basically the same as commit 9d42d48 from Catalin Marinas but adopted to the parisc architecture.

The native (64-bit) sigval_t union contains sival_int (32-bit) and sival_ptr (64-bit). When a compat application invokes a syscall that takes a sigval_t value (as part of a larger structure, e.g. compat_sys_mq_notify, compat_sys_timer_create), the compat_sigval_t union is converted to the native sigval_t with sival_int overlapping with either the least or the most significant half of sival_ptr, depending on endianness. When the corresponding signal is delivered to a compat application, on big endian the current (compat_uptr_t)sival_ptr cast always returns 0 since sival_int corresponds to the top part of sival_ptr. This patch fixes copy_siginfo_to_user32() so that sival_int is copied to the compat_siginfo_t structure.

Cc <[email protected]>
Reported-by Bamvor Jian Zhang <[email protected]>
Signed-off-by Helge Deller <[email protected]>
arch/parisc/kernel/signal32.c +2 -5
index 984abbe..d1f1fcd 100644
@@ -322,7 +322,6 @@ int
 copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from)
 {
 	compat_uptr_t addr;
-	compat_int_t val;
 	int err;
 
 	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))

@@ -361,15 +360,13 @@ copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from)
 		case __SI_TIMER >> 16:
 			err |= __put_user(from->si_tid, &to->si_tid);
 			err |= __put_user(from->si_overrun, &to->si_overrun);
-			val = (compat_int_t)from->si_int;
-			err |= __put_user(val, &to->si_int);
+			err |= __put_user(from->si_int, &to->si_int);
 			break;
 		case __SI_RT >> 16:	/* Not generated by the kernel as of now.  */
 		case __SI_MESGQ >> 16:
 			err |= __put_user(from->si_uid, &to->si_uid);
 			err |= __put_user(from->si_pid, &to->si_pid);
-			val = (compat_int_t)from->si_int;
-			err |= __put_user(val, &to->si_int);
+			err |= __put_user(from->si_int, &to->si_int);
 			break;
 		}
 	}
#1 lore raw
Quoted 13 lines · Helge Deller

This patch is basically the same as commit 9d42d48 from Catalin Marinas but adopted to the parisc architecture.

The native (64-bit) sigval_t union contains sival_int (32-bit) and sival_ptr (64-bit). When a compat application invokes a syscall that takes a sigval_t value (as part of a larger structure, e.g. compat_sys_mq_notify, compat_sys_timer_create), the compat_sigval_t union is converted to the native sigval_t with sival_int overlapping with either the least or the most significant half of sival_ptr, depending on endianness. When the corresponding signal is delivered to a compat application, on big endian the current (compat_uptr_t)sival_ptr cast always returns 0 since sival_int corresponds to the top part of sival_ptr. This patch fixes copy_siginfo_to_user32() so that sival_int is copied to the compat_siginfo_t structure.

Se below, I don't think this patch is needed.

Quoted 13 lines
arch/parisc/kernel/signal32.c +0 -1
index 984abbe..d1f1fcd 100644
@@ -322,7 +322,6 @@ int
 copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from)
 {
 	compat_uptr_t addr;
-	compat_int_t val;
 	int err;
 
 	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))

arch/parisc/kernel/signal32.c copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from) · line 363

Quoted 6 lines
arch/parisc/kernel/signal32.c +1 -2
@@ -361,15 +360,13 @@ copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from)
 		case __SI_TIMER >> 16:
 			err |= __put_user(from->si_tid, &to->si_tid);
 			err |= __put_user(from->si_overrun, &to->si_overrun);
-			val = (compat_int_t)from->si_int;
-			err |= __put_user(val, &to->si_int);
+			err |= __put_user(from->si_int, &to->si_int);

Is there any actual change here? The native si_int is 32-bit already, same as compat_int_t. I didn't think parisc needed fixing (only if it was using si_ptr which is 64-bit on a 64-bit architecture).

arch/parisc/kernel/signal32.c copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from) · line 369

Quoted 8 lines
arch/parisc/kernel/signal32.c +1 -2
 			break;
 		case __SI_RT >> 16:	/* Not generated by the kernel as of now.  */
 		case __SI_MESGQ >> 16:
 			err |= __put_user(from->si_uid, &to->si_uid);
 			err |= __put_user(from->si_pid, &to->si_pid);
-			val = (compat_int_t)from->si_int;
-			err |= __put_user(val, &to->si_int);
+			err |= __put_user(from->si_int, &to->si_int);

Same here.

Signature · 1 line
Catalin