diff options
| -rw-r--r-- | fs/exec.c | 50 |
1 files changed, 34 insertions, 16 deletions
diff --git a/fs/exec.c b/fs/exec.c index 3155e915307a..f1691cd0c9d2 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); /* |