The patch titled
Subject: exec: open code copy_string_kernel
has been removed from the -mm tree. Its filename was
exec-open-code-copy_string_kernel.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: exec: open code copy_string_kernel
Currently copy_string_kernel is just a wrapper around copy_strings that
simplifies the calling conventions and uses set_fs to allow passing a
kernel pointer. But due to the fact the we only need to handle a single
kernel argument pointer, the logic can be sigificantly simplified while
getting rid of the set_fs.
Link: http://lkml.kernel.org/r/20200501104105.2621149-3-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 45 +++++++++++++++++++++++++++++++++++----------
1 file changed, 35 insertions(+), 10 deletions(-)
--- a/fs/exec.c~exec-open-code-copy_string_kernel
+++ a/fs/exec.c
@@ -592,17 +592,42 @@ out:
*/
int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
{
- int r;
- mm_segment_t oldfs = get_fs();
- struct user_arg_ptr argv = {
- .ptr.native = (const char __user *const __user *)&arg,
- };
-
- set_fs(KERNEL_DS);
- r = copy_strings(1, argv, bprm);
- set_fs(oldfs);
+ int len = strnlen(arg, MAX_ARG_STRLEN) + 1 /* terminating NUL */;
+ unsigned long pos = bprm->p;
- return r;
+ if (len == 0)
+ return -EFAULT;
+ if (!valid_arg_len(bprm, len))
+ return -E2BIG;
+
+ /* We're going to work our way backwards. */
+ arg += len;
+ bprm->p -= len;
+ if (IS_ENABLED(CONFIG_MMU) && bprm->p < bprm->argmin)
+ return -E2BIG;
+
+ while (len > 0) {
+ unsigned int bytes_to_copy = min_t(unsigned int, len,
+ min_not_zero(offset_in_page(pos), PAGE_SIZE));
+ struct page *page;
+ char *kaddr;
+
+ pos -= bytes_to_copy;
+ arg -= bytes_to_copy;
+ len -= bytes_to_copy;
+
+ page = get_arg_page(bprm, pos, 1);
+ if (!page)
+ return -E2BIG;
+ kaddr = kmap_atomic(page);
+ flush_arg_page(bprm, pos & PAGE_MASK, page);
+ memcpy(kaddr + offset_in_page(pos), arg, bytes_to_copy);
+ flush_kernel_dcache_page(page);
+ kunmap_atomic(kaddr);
+ put_arg_page(page);
+ }
+
+ return 0;
}
EXPORT_SYMBOL(copy_string_kernel);
_
Patches currently in -mm which might be from hch@xxxxxx are
amdgpu-a-null-mm-does-not-mean-a-thread-is-a-kthread.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
arm-fix-the-flush_icache_range-arguments-in-set_fiq_handler.patch
nds32-unexport-flush_icache_page.patch
powerpc-unexport-flush_icache_user_range.patch
unicore32-remove-flush_cache_user_range.patch
asm-generic-fix-the-inclusion-guards-for-cacheflushh.patch
asm-generic-dont-include-linux-mmh-in-cacheflushh.patch
asm-generic-dont-include-linux-mmh-in-cacheflushh-fix.patch
asm-generic-improve-the-flush_dcache_page-stub.patch
alpha-use-asm-generic-cacheflushh.patch
arm64-use-asm-generic-cacheflushh.patch
c6x-use-asm-generic-cacheflushh.patch
hexagon-use-asm-generic-cacheflushh.patch
ia64-use-asm-generic-cacheflushh.patch
microblaze-use-asm-generic-cacheflushh.patch
m68knommu-use-asm-generic-cacheflushh.patch
openrisc-use-asm-generic-cacheflushh.patch
powerpc-use-asm-generic-cacheflushh.patch
riscv-use-asm-generic-cacheflushh.patch
armsparcunicore32-remove-flush_icache_user_range.patch
mm-rename-flush_icache_user_range-to-flush_icache_user_page.patch
asm-generic-add-a-flush_icache_user_range-stub.patch
sh-implement-flush_icache_user_range.patch
xtensa-implement-flush_icache_user_range.patch
arm-rename-flush_cache_user_range-to-flush_icache_user_range.patch
m68k-implement-flush_icache_user_range.patch
exec-only-build-read_code-when-needed.patch
exec-use-flush_icache_user_range-in-read_code.patch
binfmt_flat-use-flush_icache_user_range.patch
nommu-use-flush_icache_user_range-in-brk-and-mmap.patch
module-move-the-set_fs-hack-for-flush_icache_range-to-m68k.patch
maccess-unexport-probe_kernel_write-and-probe_user_write.patch
maccess-remove-various-unused-weak-aliases.patch
maccess-remove-duplicate-kerneldoc-comments.patch
maccess-clarify-kerneldoc-comments.patch
maccess-update-the-top-of-file-comment.patch
maccess-rename-strncpy_from_unsafe_user-to-strncpy_from_user_nofault.patch
maccess-rename-strncpy_from_unsafe_strict-to-strncpy_from_kernel_nofault.patch
maccess-rename-strnlen_unsafe_user-to-strnlen_user_nofault.patch
maccess-remove-probe_read_common-and-probe_write_common.patch
maccess-unify-the-probe-kernel-arch-hooks.patch
bpf-factor-out-a-bpf_trace_copy_string-helper.patch
bpf-handle-the-compat-string-in-bpf_trace_copy_string-better.patch
bpf-rework-the-compat-kernel-probe-handling.patch
tracing-kprobes-handle-mixed-kernel-userspace-probes-better.patch
maccess-remove-strncpy_from_unsafe.patch
maccess-always-use-strict-semantics-for-probe_kernel_read.patch
maccess-move-user-access-routines-together.patch
maccess-allow-architectures-to-provide-kernel-probing-directly.patch
x86-use-non-set_fs-based-maccess-routines.patch
maccess-return-erange-when-copy_from_kernel_nofault_allowed-fails.patch
