The patch titled
Subject: binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump
has been added to the -mm tree. Its filename is
binfmt_elf-remove-the-set_fskernel_ds-in-elf_core_dump.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/binfmt_elf-remove-the-set_fskernel_ds-in-elf_core_dump.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/binfmt_elf-remove-the-set_fskernel_ds-in-elf_core_dump.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump
There is no logic in elf_core_dump itself, or in the various arch helpers
called from it which use uaccess routines on kernel pointers except for
the file writes thate are nicely encapsulated by using __kernel_write in
dump_emit.
Link: http://lkml.kernel.org/r/20200421154204.252921-5-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: "Eric W . Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Jeremy Kerr <jk@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 40 +++++++++++++---------------------------
1 file changed, 13 insertions(+), 27 deletions(-)
--- a/fs/binfmt_elf.c~binfmt_elf-remove-the-set_fskernel_ds-in-elf_core_dump
+++ a/fs/binfmt_elf.c
@@ -1351,7 +1351,6 @@ static unsigned long vma_dump_size(struc
vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
u32 __user *header = (u32 __user *) vma->vm_start;
u32 word;
- mm_segment_t fs = get_fs();
/*
* Doing it this way gets the constant folded by GCC.
*/
@@ -1364,14 +1363,8 @@ static unsigned long vma_dump_size(struc
magic.elfmag[EI_MAG1] = ELFMAG1;
magic.elfmag[EI_MAG2] = ELFMAG2;
magic.elfmag[EI_MAG3] = ELFMAG3;
- /*
- * Switch to the user "segment" for get_user(),
- * then put back what elf_core_dump() had in place.
- */
- set_fs(USER_DS);
if (unlikely(get_user(word, header)))
word = 0;
- set_fs(fs);
if (word == magic.cmp)
return PAGE_SIZE;
}
@@ -2179,7 +2172,6 @@ static void fill_extnum_info(struct elfh
static int elf_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
- mm_segment_t fs;
int segs, i;
size_t vma_data_size = 0;
struct vm_area_struct *vma, *gate_vma;
@@ -2232,9 +2224,6 @@ static int elf_core_dump(struct coredump
has_dumped = 1;
- fs = get_fs();
- set_fs(KERNEL_DS);
-
offset += sizeof(elf); /* Elf header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */
@@ -2246,7 +2235,7 @@ static int elf_core_dump(struct coredump
phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
if (!phdr4note)
- goto end_coredump;
+ goto cleanup;
fill_elf_note_phdr(phdr4note, sz, offset);
offset += sz;
@@ -2261,7 +2250,7 @@ static int elf_core_dump(struct coredump
vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)),
GFP_KERNEL);
if (!vma_filesz)
- goto end_coredump;
+ goto cleanup;
for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
@@ -2279,17 +2268,17 @@ static int elf_core_dump(struct coredump
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
- goto end_coredump;
+ goto cleanup;
fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
}
offset = dataoff;
if (!dump_emit(cprm, &elf, sizeof(elf)))
- goto end_coredump;
+ goto cleanup;
if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
- goto end_coredump;
+ goto cleanup;
/* Write program headers for segments dump */
for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
@@ -2311,22 +2300,22 @@ static int elf_core_dump(struct coredump
phdr.p_align = ELF_EXEC_PAGESIZE;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
- goto end_coredump;
+ goto cleanup;
}
if (!elf_core_write_extra_phdrs(cprm, offset))
- goto end_coredump;
+ goto cleanup;
/* write out the notes section */
if (!write_note_info(&info, cprm))
- goto end_coredump;
+ goto cleanup;
if (elf_coredump_extra_notes_write(cprm))
- goto end_coredump;
+ goto cleanup;
/* Align to page */
if (!dump_skip(cprm, dataoff - cprm->pos))
- goto end_coredump;
+ goto cleanup;
for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
@@ -2348,22 +2337,19 @@ static int elf_core_dump(struct coredump
} else
stop = !dump_skip(cprm, PAGE_SIZE);
if (stop)
- goto end_coredump;
+ goto cleanup;
}
}
dump_truncate(cprm);
if (!elf_core_write_extra_data(cprm))
- goto end_coredump;
+ goto cleanup;
if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
- goto end_coredump;
+ goto cleanup;
}
-end_coredump:
- set_fs(fs);
-
cleanup:
free_note_info(&info);
kfree(shdr4extnum);
_
Patches currently in -mm which might be from hch@xxxxxx are
x86-hyperv-use-vmalloc_exec-for-the-hypercall-page.patch
x86-fix-vmap-arguments-in-map_irq_stack.patch
staging-android-ion-use-vmap-instead-of-vm_map_ram.patch
staging-media-ipu3-use-vmap-instead-of-reimplementing-it.patch
dma-mapping-use-vmap-insted-of-reimplementing-it.patch
powerpc-add-an-ioremap_phb-helper.patch
powerpc-remove-__ioremap_at-and-__iounmap_at.patch
mm-remove-__get_vm_area.patch
mm-unexport-unmap_kernel_range_noflush.patch
mm-rename-config_pgtable_mapping-to-config_zsmalloc_pgtable_mapping.patch
mm-only-allow-page-table-mappings-for-built-in-zsmalloc.patch
mm-pass-addr-as-unsigned-long-to-vb_free.patch
mm-remove-vmap_page_range_noflush-and-vunmap_page_range.patch
mm-rename-vmap_page_range-to-map_kernel_range.patch
mm-dont-return-the-number-of-pages-from-map_kernel_range_noflush.patch
mm-remove-map_vm_range.patch
mm-remove-unmap_vmap_area.patch
mm-remove-the-prot-argument-from-vm_map_ram.patch
mm-enforce-that-vmap-cant-map-pages-executable.patch
gpu-drm-remove-the-powerpc-hack-in-drm_legacy_sg_alloc.patch
mm-remove-the-pgprot-argument-to-__vmalloc.patch
mm-remove-the-prot-argument-to-__vmalloc_node.patch
mm-remove-both-instances-of-__vmalloc_node_flags.patch
mm-remove-__vmalloc_node_flags_caller.patch
mm-switch-the-test_vmalloc-module-to-use-__vmalloc_node.patch
mm-remove-vmalloc_user_node_flags.patch
arm64-use-__vmalloc_node-in-arch_alloc_vmap_stack.patch
powerpc-use-__vmalloc_node-in-alloc_vm_stack.patch
s390-use-__vmalloc_node-in-stack_alloc.patch
powerpc-spufs-simplify-spufs-core-dumping.patch
binfmt_elf-remove-the-set_fskernel_ds-in-elf_core_dump.patch
binfmt_elf_fdpic-remove-the-set_fskernel_ds-in-elf_fdpic_core_dump.patch
exec-simplify-the-copy_strings_kernel-calling-convention.patch
exec-open-code-copy_string_kernel.patch
amdgpu-a-null-mm-does-not-mean-a-thread-is-a-kthread.patch
i915-gvt-remove-unused-xen-bits.patch
kernel-move-use_mm-unuse_mm-to-kthreadc.patch
kernel-move-use_mm-unuse_mm-to-kthreadc-v2.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract-v2.patch
kernel-set-user_ds-in-kthread_use_mm.patch
