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-rw-r--r--fs/exec.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 3155e91..f1691cd 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -982,33 +982,51 @@ void compute_creds(struct linux_binprm *bprm)
task_unlock(current);
security_bprm_post_apply_creds(bprm);
}
-
EXPORT_SYMBOL(compute_creds);
+/*
+ * Arguments are '\0' separated strings found at the location bprm->p
+ * points to; chop off the first by relocating brpm->p to right after
+ * the first '\0' encountered.
+ */
void remove_arg_zero(struct linux_binprm *bprm)
{
if (bprm->argc) {
- unsigned long offset;
- char * kaddr;
- struct page *page;
+ char ch;
- offset = bprm->p % PAGE_SIZE;
- goto inside;
+ do {
+ unsigned long offset;
+ unsigned long index;
+ char *kaddr;
+ struct page *page;
- while (bprm->p++, *(kaddr+offset++)) {
- if (offset != PAGE_SIZE)
- continue;
- offset = 0;
- kunmap_atomic(kaddr, KM_USER0);
-inside:
- page = bprm->page[bprm->p/PAGE_SIZE];
+ offset = bprm->p & ~PAGE_MASK;
+ index = bprm->p >> PAGE_SHIFT;
+
+ page = bprm->page[index];
kaddr = kmap_atomic(page, KM_USER0);
- }
- kunmap_atomic(kaddr, KM_USER0);
+
+ /* run through page until we reach end or find NUL */
+ do {
+ ch = *(kaddr + offset);
+
+ /* discard that character... */
+ bprm->p++;
+ offset++;
+ } while (offset < PAGE_SIZE && ch != '\0');
+
+ kunmap_atomic(kaddr, KM_USER0);
+
+ /* free the old page */
+ if (offset == PAGE_SIZE) {
+ __free_page(page);
+ bprm->page[index] = NULL;
+ }
+ } while (ch != '\0');
+
bprm->argc--;
}
}
-
EXPORT_SYMBOL(remove_arg_zero);
/*
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