The return code for attempting to execute a directory has always been EACCES. Adjust the S_ISDIR exec test to reflect the old errno instead of the general EISDIR for other kinds of "open" attempts on directories. Reported-by: Marc Zyngier <maz@xxxxxxxxxx> Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier") Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- fs/namei.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/namei.c b/fs/namei.c index 2112e578dccc..e99e2a9da0f7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2849,8 +2849,10 @@ static int may_open(const struct path *path, int acc_mode, int flag) case S_IFLNK: return -ELOOP; case S_IFDIR: - if (acc_mode & (MAY_WRITE | MAY_EXEC)) + if (acc_mode & MAY_WRITE) return -EISDIR; + if (acc_mode & MAY_EXEC) + return -EACCES; break; case S_IFBLK: case S_IFCHR: -- 2.25.1
