From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: exec: restore EACCES of S_ISDIR execve() Patch series "Fix S_ISDIR execve() errno". Fix an errno change for execve() of directories, noticed by Marc Zyngier. Along with the fix, include a regression test to avoid seeing this return in the future. This patch (of 2): 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. Link: http://lkml.kernel.org/r/20200813231723.2725102-2-keescook@xxxxxxxxxxxx Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier") Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Reported-by: Marc Zyngier <maz@xxxxxxxxxx> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxx> Tested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/namei.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/namei.c~exec-restore-eacces-of-s_isdir-execve +++ a/fs/namei.c @@ -2849,8 +2849,10 @@ static int may_open(const struct path *p 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: _
