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authorAl Viro <viro@ftp.linux.org.uk>2010-09-20 15:13:09 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-20 10:44:37 -0700
commit5f4ad04a1e805d14de080ff9d5384b4d20518a9a (patch)
tree63252b79b48b7dfd29d9a8081a34c858dab1de74 /arch/frv/kernel
parent20cd514d0f3d288d968217028ca67b70e707d896 (diff)
downloadlinux-5f4ad04a1e805d14de080ff9d5384b4d20518a9a.tar.gz
frv: fix address verification holes in setup_frame/setup_rt_frame
a) sa_handler might be maliciously set to point to kernel memory; blindly dereferencing it in FDPIC case is a Bad Idea(tm). b) I'm not sure you need that set_fs(USER_DS) there at all, but if you do, you'd better do it *before* checking the frame you've decided to use with access_ok(), lest sigaltstack() becomes a convenient roothole. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/frv/kernel')
-rw-r--r--arch/frv/kernel/signal.c38
1 files changed, 22 insertions, 16 deletions
diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c
index 7fc29615ef0..5fb2d0661c7 100644
--- a/arch/frv/kernel/signal.c
+++ b/arch/frv/kernel/signal.c
@@ -253,6 +253,8 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
struct sigframe __user *frame;
int rsig;
+ set_fs(USER_DS);
+
frame = get_sigframe(ka, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
@@ -296,22 +298,23 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
(unsigned long) (frame->retcode + 2));
}
- /* set up registers for signal handler */
- __frame->sp = (unsigned long) frame;
- __frame->lr = (unsigned long) &frame->retcode;
- __frame->gr8 = sig;
-
+ /* Set up registers for the signal handler */
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
- __get_user(__frame->pc, &funcptr->text);
- __get_user(__frame->gr15, &funcptr->GOT);
+ struct fdpic_func_descriptor desc;
+ if (copy_from_user(&desc, funcptr, sizeof(desc)))
+ goto give_sigsegv;
+ __frame->pc = desc.text;
+ __frame->gr15 = desc.GOT;
} else {
__frame->pc = (unsigned long) ka->sa.sa_handler;
__frame->gr15 = 0;
}
- set_fs(USER_DS);
+ __frame->sp = (unsigned long) frame;
+ __frame->lr = (unsigned long) &frame->retcode;
+ __frame->gr8 = sig;
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))
@@ -341,6 +344,8 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
struct rt_sigframe __user *frame;
int rsig;
+ set_fs(USER_DS);
+
frame = get_sigframe(ka, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
@@ -395,22 +400,23 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
}
/* Set up registers for signal handler */
- __frame->sp = (unsigned long) frame;
- __frame->lr = (unsigned long) &frame->retcode;
- __frame->gr8 = sig;
- __frame->gr9 = (unsigned long) &frame->info;
-
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
- __get_user(__frame->pc, &funcptr->text);
- __get_user(__frame->gr15, &funcptr->GOT);
+ struct fdpic_func_descriptor desc;
+ if (copy_from_user(&desc, funcptr, sizeof(desc)))
+ goto give_sigsegv;
+ __frame->pc = desc.text;
+ __frame->gr15 = desc.GOT;
} else {
__frame->pc = (unsigned long) ka->sa.sa_handler;
__frame->gr15 = 0;
}
- set_fs(USER_DS);
+ __frame->sp = (unsigned long) frame;
+ __frame->lr = (unsigned long) &frame->retcode;
+ __frame->gr8 = sig;
+ __frame->gr9 = (unsigned long) &frame->info;
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))