The patch titled
Subject: fs/binfmt_elf.c: coredump: allocate core ELF header on stack
has been added to the -mm tree. Its filename is
elf-coredump-allocate-core-elf-header-on-stack.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/elf-coredump-allocate-core-elf-header-on-stack.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/elf-coredump-allocate-core-elf-header-on-stack.patch
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------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: fs/binfmt_elf.c: coredump: allocate core ELF header on stack
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 <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
--- a/fs/binfmt_elf.c~elf-coredump-allocate-core-elf-header-on-stack
+++ a/fs/binfmt_elf.c
@@ -2186,7 +2186,7 @@ static int elf_core_dump(struct coredump
int segs, i;
size_t vma_data_size = 0;
struct vm_area_struct *vma, *gate_vma;
- struct elfhdr *elf = NULL;
+ struct elfhdr elf;
loff_t offset = 0, dataoff;
struct elf_note_info info = { };
struct elf_phdr *phdr4note = NULL;
@@ -2207,10 +2207,6 @@ static int elf_core_dump(struct coredump
* exists while dumping the mm->vm_next areas to the core file.
*/
- /* alloc memory for large data structures: too large to be on stack */
- elf = kmalloc(sizeof(*elf), GFP_KERNEL);
- if (!elf)
- goto out;
/*
* The number of segs are recored into ELF header as 16bit value.
* Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
@@ -2234,7 +2230,7 @@ static int elf_core_dump(struct coredump
* Collect all the non-memory information about the process for the
* notes. This also sets up the file header.
*/
- if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs))
+ if (!fill_note_info(&elf, e_phnum, &info, cprm->siginfo, cprm->regs))
goto cleanup;
has_dumped = 1;
@@ -2242,7 +2238,7 @@ static int elf_core_dump(struct coredump
fs = get_fs();
set_fs(KERNEL_DS);
- offset += sizeof(*elf); /* Elf header */
+ offset += sizeof(elf); /* Elf header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */
/* Write notes phdr entry */
@@ -2285,12 +2281,12 @@ static int elf_core_dump(struct coredump
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
goto end_coredump;
- fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
+ fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
}
offset = dataoff;
- if (!dump_emit(cprm, elf, sizeof(*elf)))
+ if (!dump_emit(cprm, &elf, sizeof(elf)))
goto end_coredump;
if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
@@ -2374,8 +2370,6 @@ cleanup:
kfree(shdr4extnum);
kvfree(vma_filesz);
kfree(phdr4note);
- kfree(elf);
-out:
return has_dumped;
}
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
ramfs-support-o_tmpfile.patch
elf-smaller-code-generation-around-auxv-vector-fill.patch
elf-fix-start_code-calculation.patch
elf-dont-copy-elf-header-around.patch
elf-better-codegen-around-current-mm.patch
elf-make-bad_addr-unlikely.patch
elf-coredump-allocate-core-elf-header-on-stack.patch
execve-warn-if-process-starts-with-executable-stack.patch
