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authorZachary Amsden <zach@vmware.com>2005-09-03 18:56:43 -0400
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 03:06:12 -0400
commit0998e4228aca046fbd747c3fed909791d52e88eb (patch)
tree314cb04a6223100bf468cc420985bfe7e3680d44 /arch
parentf2ab4461249df85b20930a7a57b54f39c5ae291a (diff)
[PATCH] x86: privilege cleanup
Privilege checking cleanup. Originally, these diffs were much greater, but recent cleanups in Linux have already done much of the cleanup. I added some explanatory comments in places where the reasoning behind certain tests is rather subtle. Also, in traps.c, we can skip the user_mode check in handle_BUG(). The reason is, there are only two call chains - one via die_if_kernel() and one via do_page_fault(), both entering from die(). Both of these paths already ensure that a kernel mode failure has happened. Also, the original check here, if (user_mode(regs)) was insufficient anyways, since it would not rule out BUG faults from V8086 mode execution. Saving the %ss segment in show_regs() rather than assuming a fixed value also gives better information about the current kernel state in the register dump. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/kernel/signal.c4
-rw-r--r--arch/i386/kernel/traps.c5
2 files changed, 4 insertions, 5 deletions
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
index 7bcda6d69d87..61eb0c8a6e47 100644
--- a/arch/i386/kernel/signal.c
+++ b/arch/i386/kernel/signal.c
@@ -604,7 +604,9 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
604 * We want the common case to go fast, which 604 * We want the common case to go fast, which
605 * is why we may in certain cases get here from 605 * is why we may in certain cases get here from
606 * kernel mode. Just return without doing anything 606 * kernel mode. Just return without doing anything
607 * if so. 607 * if so. vm86 regs switched out by assembly code
608 * before reaching here, so testing against kernel
609 * CS suffices.
608 */ 610 */
609 if (!user_mode(regs)) 611 if (!user_mode(regs))
610 return 1; 612 return 1;
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 1144df0c48d6..b2b4bb890bb7 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -210,7 +210,7 @@ void show_registers(struct pt_regs *regs)
210 unsigned short ss; 210 unsigned short ss;
211 211
212 esp = (unsigned long) (&regs->esp); 212 esp = (unsigned long) (&regs->esp);
213 ss = __KERNEL_DS; 213 savesegment(ss, ss);
214 if (user_mode(regs)) { 214 if (user_mode(regs)) {
215 in_kernel = 0; 215 in_kernel = 0;
216 esp = regs->esp; 216 esp = regs->esp;
@@ -267,9 +267,6 @@ static void handle_BUG(struct pt_regs *regs)
267 char c; 267 char c;
268 unsigned long eip; 268 unsigned long eip;
269 269
270 if (user_mode(regs))
271 goto no_bug; /* Not in kernel */
272
273 eip = regs->eip; 270 eip = regs->eip;
274 271
275 if (eip < PAGE_OFFSET) 272 if (eip < PAGE_OFFSET)