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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 19:18:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 19:18:29 -0700
commit886d7de631da71e30909980fdbf318f7caade262 (patch)
treed79c741b609098ec8c8a3643ba52f26e6a2cd4d1 /fs/exec.c
parent5bfea2d9b17f1034a68147a8b03b9789af5700f9 (diff)
parent469cbd016157d28c27fda8da6ddc76b856f4e1b9 (diff)
Merge branch 'akpm' (patches from Andrew)
Merge yet more updates from Andrew Morton: - More MM work. 100ish more to go. Mike Rapoport's "mm: remove __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue - Various other little subsystems * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits) lib/ubsan.c: fix gcc-10 warnings tools/testing/selftests/vm: remove duplicate headers selftests: vm: pkeys: fix multilib builds for x86 selftests: vm: pkeys: use the correct page size on powerpc selftests/vm/pkeys: override access right definitions on powerpc selftests/vm/pkeys: test correct behaviour of pkey-0 selftests/vm/pkeys: introduce a sub-page allocator selftests/vm/pkeys: detect write violation on a mapped access-denied-key page selftests/vm/pkeys: associate key on a mapped page and detect write violation selftests/vm/pkeys: associate key on a mapped page and detect access violation selftests/vm/pkeys: improve checks to determine pkey support selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust() selftests/vm/pkeys: fix number of reserved powerpc pkeys selftests/vm/pkeys: introduce powerpc support selftests/vm/pkeys: introduce generic pkey abstractions selftests: vm: pkeys: use the correct huge page size selftests/vm/pkeys: fix alloc_random_pkey() to make it really random selftests/vm/pkeys: fix assertion in pkey_disable_set/clear() selftests/vm/pkeys: fix pkey_disable_clear() selftests: vm: pkeys: add helpers for pkey bits ...
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c52
1 files changed, 38 insertions, 14 deletions
diff --git a/fs/exec.c b/fs/exec.c
index e850ee7dd636..93ff1c4c7ebb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -590,24 +590,48 @@ out:
}
/*
- * Like copy_strings, but get argv and its values from kernel memory.
+ * Copy and argument/environment string from the kernel to the processes stack.
*/
-int copy_strings_kernel(int argc, const char *const *__argv,
- struct linux_binprm *bprm)
+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 *)__argv,
- };
+ int len = strnlen(arg, MAX_ARG_STRLEN) + 1 /* terminating NUL */;
+ unsigned long pos = bprm->p;
+
+ 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;
- set_fs(KERNEL_DS);
- r = copy_strings(argc, argv, bprm);
- set_fs(oldfs);
+ 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;
- return r;
+ 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_strings_kernel);
+EXPORT_SYMBOL(copy_string_kernel);
#ifdef CONFIG_MMU
@@ -1883,7 +1907,7 @@ static int __do_execve_file(int fd, struct filename *filename,
if (retval)
goto out;
- retval = copy_strings_kernel(1, &bprm->filename, bprm);
+ retval = copy_string_kernel(bprm->filename, bprm);
if (retval < 0)
goto out;