Commit fa4751f4 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Al Viro
Browse files

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: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c3b3f524

fs/binfmt_elf.c

+1 −4
Original line number Diff line number Diff line
@@ -1556,10 +1556,7 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) 
static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,

		const kernel_siginfo_t *siginfo)

{

	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);

	copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);

	set_fs(old_fs);

	copy_siginfo_to_external(csigdata, siginfo);

	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);

}

fs/compat_binfmt_elf.c

+1 −1
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ 
 */

#define user_long_t		compat_long_t

#define user_siginfo_t		compat_siginfo_t

#define copy_siginfo_to_user	copy_siginfo_to_user32

#define copy_siginfo_to_external	copy_siginfo_to_external32



/*

 * The machine-dependent core note format types are defined in elfcore-compat.h,

include/linux/signal.h

+8 −0
Original line number Diff line number Diff line
@@ -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);

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