diff mbox series

[1/2] exec: Restore EACCES of S_ISDIR execve()

Message ID 20200813231723.2725102-2-keescook@chromium.org (mailing list archive)
State Mainlined
Commit fc4177be963dccad73b98d7db3a8a38911f952b7
Headers show
Series Fix S_ISDIR execve() errno | expand

Commit Message

Kees Cook Aug. 13, 2020, 11:17 p.m. UTC
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@kernel.org>
Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/namei.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Greg KH Aug. 14, 2020, 7:11 a.m. UTC | #1
On Thu, Aug 13, 2020 at 04:17:22PM -0700, Kees Cook wrote:
> 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@kernel.org>
> Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  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:


Reviewed-by: Greg Kroah-Hartman <gregkh@google.com>
Greg KH Aug. 14, 2020, 8:13 a.m. UTC | #2
On Fri, Aug 14, 2020 at 09:11:02AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Aug 13, 2020 at 04:17:22PM -0700, Kees Cook wrote:
> > 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@kernel.org>
> > Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> > Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  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:
> 
> 
> Reviewed-by: Greg Kroah-Hartman <gregkh@google.com>

And to round out the "let's use a different email address for each
response, to drive accounting tools crazy!" effort, you can also add:

Tested-by: Greg Kroah-Hartman <gregkh@android.com>

thanks,

greg "I don't have enough different email addresses" k-h
Marc Zyngier Aug. 14, 2020, 8:15 a.m. UTC | #3
On 2020-08-14 00:17, Kees Cook wrote:
> 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@kernel.org>
> Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  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:

Reviewed-by: Marc Zyngier <maz@kernel.org>

         M.
diff mbox series

Patch

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: