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authorJia Zhang <zhang.jia@linux.alibaba.com>2018-02-12 22:44:53 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-30 07:50:26 +0200
commit059befd4e0ae7ad7c54d5d292a3cb75b51ff4bf9 (patch)
tree299d5a9eca5409f452b52ae1e9257e7adc68cec7 /fs
parent517fbc77e8b44eed689d1576245e16a62a647f22 (diff)
vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page
[ Upstream commit 595dd46ebfc10be041a365d0a3fa99df50b6ba73 ] Commit: df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") ... introduced a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y. However, accessing the vsyscall user page will cause an SMAP fault. Replace memcpy() with copy_from_user() to fix this bug works, but adding a common way to handle this sort of user page may be useful for future. Currently, only vsyscall page requires KCORE_USER. Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/kcore.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index df7e07986ead..7ed961c0124f 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -505,6 +505,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
/* we have to zero-fill user buffer even if no read */
if (copy_to_user(buffer, buf, tsz))
return -EFAULT;
+ } else if (m->type == KCORE_USER) {
+ /* User page is handled prior to normal kernel page: */
+ if (copy_to_user(buffer, (char *)start, tsz))
+ return -EFAULT;
} else {
if (kern_addr_valid(start)) {
/*