linux.git/fs/binfmt_elf.c, branch v5.7

fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info()

2020-05-28T18:35:40+00:00

KMSAN reported uninitialized data being written to disk when dumping
core.  As a result, several kilobytes of kmalloc memory may be written
to the core file and then read by a non-privileged user.

Reported-by: sam 
Signed-off-by: Alexander Potapenko 
Signed-off-by: Andrew Morton 
Acked-by: Kees Cook 
Cc: Al Viro 
Cc: Alexey Dobriyan 
Cc: 
Link: http://lkml.kernel.org/r/20200419100848.63472-1-glider@google.com
Link: https://github.com/google/kmsan/issues/76
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: don't free interpreter's ELF pheaders on common path

2020-04-07T17:43:44+00:00

Static executables don't need to free NULL pointer.

It doesn't matter really because static executable is not common scenario
but do it anyway out of pedantry.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200219185330.GA4933@avx2
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: allocate less for static executable

2020-04-07T17:43:44+00:00

PT_INTERP ELF header can be spared if executable is static.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200219185012.GB4871@avx2
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: delete "loc" variable

2020-04-07T17:43:44+00:00

"loc" variable became just a wrapper for PT_INTERP ELF header after main
ELF header was moved to "bprm->buf".  Delete it.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200219184847.GA4871@avx2
Signed-off-by: Linus Torvalds

mm/vma: replace all remaining open encodings with is_vm_hugetlb_page()

2020-04-07T17:43:37+00:00

This replaces all remaining open encodings with is_vm_hugetlb_page().

Signed-off-by: Anshuman Khandual 
Signed-off-by: Andrew Morton 
Acked-by: Vlastimil Babka 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Michael Ellerman 
Cc: Alexander Viro 
Cc: Will Deacon 
Cc: "Aneesh Kumar K.V" 
Cc: Nick Piggin 
Cc: Peter Zijlstra 
Cc: Arnd Bergmann 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: Andy Lutomirski 
Cc: Dave Hansen 
Cc: Geert Uytterhoeven 
Cc: Guo Ren 
Cc: Mel Gorman 
Cc: Paul Burton 
Cc: Paul Mackerras 
Cc: Ralf Baechle 
Cc: Rich Felker 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Yoshinori Sato 
Link: http://lkml.kernel.org/r/1582520593-30704-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: coredump: allow process with empty address space to coredump

2020-01-31T18:30:41+00:00

Unmapping whole address space at once with

	munmap(0, (1ULL<<47) - 4096)

or equivalent will create empty coredump.

It is silly way to exit, however registers content may still be useful.

The right to coredump is fundamental right of a process!

Link: http://lkml.kernel.org/r/20191222150137.GA1277@avx2
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: coredump: delete duplicated overflow check

2020-01-31T18:30:41+00:00

array_size() macro will do overflow check anyway.

Link: http://lkml.kernel.org/r/20191222144009.GB24341@avx2
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: coredump: allocate core ELF header on stack

2020-01-31T18:30:41+00:00

Comment says ELF header is "too large to be on stack".  64 bytes on
64-bit is not large by any means.

Link: http://lkml.kernel.org/r/20191222143850.GA24341@avx2
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: make BAD_ADDR() unlikely

2020-01-31T18:30:41+00:00

If some mapping goes past TASK_SIZE it will be rejected by kernel which
means no such userspace binaries exist.

Mark every such check as unlikely.

Link: http://lkml.kernel.org/r/20191215124355.GA21124@avx2
Signed-off-by: Alexey Dobriyan 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/binfmt_elf.c: better codegen around current->mm

2020-01-31T18:30:41+00:00

"current->mm" pointer is stable in general except few cases one of which
execve(2).  Compiler can't treat is as stable but it _is_ stable most of
the time.  During ELF loading process ->mm becomes stable right after
flush_old_exec().

Help compiler by caching current->mm, otherwise it continues to refetch
it.

	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-141 (-141)
	Function                                     old     new   delta
	elf_core_dump                               5062    5039     -23
	load_elf_binary                             5426    5308    -118

Note: other cases are left as is because it is either pessimisation or
no change in binary size.

Link: http://lkml.kernel.org/r/20191215124755.GB21124@avx2
Signed-off-by: Alexey Dobriyan 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds