The patch titled
Subject: binfmt_elf: femove the set_fs in fill_siginfo_note
has been added to the -mm tree. Its filename is
binfmt_elf-femove-the-set_fs-in-fill_siginfo_note.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/binfmt_elf-femove-the-set_fs-in-fill_siginfo_note.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/binfmt_elf-femove-the-set_fs-in-fill_siginfo_note.patch
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------------------------------------------------------
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Subject: binfmt_elf: femove the set_fs in fill_siginfo_note
The code in binfmt_elf.c is different 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 its 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.
Link: http://lkml.kernel.org/r/20200421154204.252921-4-hch@xxxxxx
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Jeremy Kerr <jk@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: "Eric W . Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 5 +----
fs/compat_binfmt_elf.c | 2 +-
include/linux/signal.h | 8 ++++++++
3 files changed, 10 insertions(+), 5 deletions(-)
--- a/fs/binfmt_elf.c~binfmt_elf-femove-the-set_fs-in-fill_siginfo_note
+++ a/fs/binfmt_elf.c
@@ -1552,10 +1552,7 @@ static void fill_auxv_note(struct memelf
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);
}
--- a/fs/compat_binfmt_elf.c~binfmt_elf-femove-the-set_fs-in-fill_siginfo_note
+++ a/fs/compat_binfmt_elf.c
@@ -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,
--- a/include/linux/signal.h~binfmt_elf-femove-the-set_fs-in-fill_siginfo_note
+++ a/include/linux/signal.h
@@ -24,6 +24,14 @@ static inline void clear_siginfo(kernel_
#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);
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
signal-factor-copy_siginfo_to_external32-from-copy_siginfo_to_user32.patch
binfmt_elf-femove-the-set_fs-in-fill_siginfo_note.patch
