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sparc64: perf: Add sanity checking on addresses in user stack

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Processes are getting killed (sigbus or segv) while walking userspace
callchains when using perf. In some instances I have seen ufp = 0x7ff
which does not seem like a proper stack address.

This patch adds a function to run validity checks against the address
before attempting the copy_from_user. The checks are copied from the
x86 version as a start point with the addition of a 4-byte alignment
check.

Signed-off-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2015-06-15 16:15:45 -04:00 • committed by David S. Miller
parent 2bf7c3efc3
commit b69fb7699c
2 changed files with 35 additions and 0 deletions
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13
arch/sparc/kernel/perf_event.c
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@ -1741,6 +1741,16 @@ void perf_callchain_kernel(struct perf_callchain_entry *entry,
} while (entry->nr < PERF_MAX_STACK_DEPTH);
}
static inline int
valid_user_frame(const void __user *fp, unsigned long size)
{
/* addresses should be at least 4-byte aligned */
if (((unsigned long) fp) & 3)
return 0;
return (__range_not_ok(fp, size, TASK_SIZE) == 0);
}
static void perf_callchain_user_64(struct perf_callchain_entry *entry,
struct pt_regs *regs)
{
@ -1753,6 +1763,9 @@ static void perf_callchain_user_64(struct perf_callchain_entry *entry,
unsigned long pc;
usf = (struct sparc_stackf __user *)ufp;
if (!valid_user_frame(usf, sizeof(sf)))
break;
if (__copy_from_user_inatomic(&sf, usf, sizeof(sf)))
break;