binfmt_elf: remove the set_fs in fill_siginfo_note

The code in binfmt_elf.c is differnt from the rest of the code that
processes siginfo, as it sends siginfo from a kernel buffer to a file
rather than from kernel memory to userspace buffers.  To remove it's
use of set_fs the code needs some different siginfo helpers.

Add the helper copy_siginfo_to_external to copy from the kernel's
internal siginfo layout to a buffer in the siginfo layout that
userspace expects.

Modify fill_siginfo_note to use copy_siginfo_to_external instead of
set_fs and copy_siginfo_to_user.

Update compat_binfmt_elf.c to use the previously added
copy_siginfo_to_external32 to handle the compat case.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 05bacd2ab135..6bb1a3f0258c 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -24,6 +24,14 @@ static inline void clear_siginfo(kernel_siginfo_t *info)
 
 #define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
 
+static inline void copy_siginfo_to_external(siginfo_t *to,
+					    const kernel_siginfo_t *from)
+{
+	memcpy(to, from, sizeof(*from));
+	memset(((char *)to) + sizeof(struct kernel_siginfo), 0,
+		SI_EXPANSION_SIZE);
+}
+
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);