Commit a75b3809 authored by Kees Cook's avatar Kees Cook
Browse files

qnx4: Use get_directory_fname() in qnx4_match() 



Use the new common directory entry name accessor helper to avoid
confusing the compiler about over-running the file name buffer. Avoids
false positive buffer overflow warning:

[ 4849.636861] detected buffer overflow in strlen
[ 4849.636897] ------------[ cut here ]------------
[ 4849.636902] kernel BUG at lib/string.c:1165!
...
[ 4849.637047] Call Trace:
...
[ 4849.637251]  qnx4_find_entry.cold+0xc/0x18 [qnx4]
[ 4849.637264]  qnx4_lookup+0x3c/0xa0 [qnx4]

Reported-by: default avatarRonald Monthero <debug.penguin32@gmail.com>
Closes: https://lore.kernel.org/lkml/20231112095353.579855-1-debug.penguin32@gmail.com/


Acked-by: default avatarAnders Larsen <al@alarsen.net>
Link: https://lore.kernel.org/r/20231130205120.3642477-2-keescook@chromium.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 53853995

fs/qnx4/namei.c

+11 −18
Original line number Diff line number Diff line
@@ -26,31 +26,24 @@ 
static int qnx4_match(int len, const char *name,

		      struct buffer_head *bh, unsigned long *offset)

{

	struct qnx4_inode_entry *de;

	int namelen, thislen;

	union qnx4_directory_entry *de;

	const char *fname;

	int fnamelen;



	if (bh == NULL) {

		printk(KERN_WARNING "qnx4: matching unassigned buffer !\n");

		return 0;

	}

	de = (struct qnx4_inode_entry *) (bh->b_data + *offset);

	de = (union qnx4_directory_entry *) (bh->b_data + *offset);

	*offset += QNX4_DIR_ENTRY_SIZE;

	if ((de->di_status & QNX4_FILE_LINK) != 0) {

		namelen = QNX4_NAME_MAX;

	} else {

		namelen = QNX4_SHORT_NAME_MAX;

	}

	thislen = strlen( de->di_fname );

	if ( thislen > namelen )

		thislen = namelen;

	if (len != thislen) {



	fname = get_entry_fname(de, &fnamelen);

	if (!fname || len != fnamelen)

		return 0;

	}

	if (strncmp(name, de->di_fname, len) == 0) {

		if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {



	if (strncmp(name, fname, len) == 0)

		return 1;

		}

	}



	return 0;

}