| Message ID | e4514426-2098-72b9-d1bb-eb5364607aef@gigawatt.nl (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
Your patch looks better than mine :) Please consider post this patch to busybox as well. Their ash has same code and same issue. See http://lists.busybox.net/pipermail/busybox/2017-May/085459.html On Fri, May 26, 2017 at 3:59 PM, Harald van Dijk <harald@gigawatt.nl> wrote: > Hi, > > On 26/05/17 09:04, Youfu Zhang wrote: >> >> $ PATH=/extra/path:/usr/sbin:/usr/bin:/sbin:/bin \ >>> >>> sh -xc 'command -V ls; command -V ls; command -Vp ls; command -vp ls' >> >> + command -V ls >> ls is /bin/ls >> + command -V ls >> ls is a tracked alias for /bin/ls >> + command -Vp ls >> ls is a tracked alias for (null) >> + command -vp ls >> Segmentation fault (core dumped) >> >> describe_command should respect `path' argument. Looking up in the hash >> table >> may gives incorrect index in entry.u.index and finally causes incorrect >> output >> or SIGSEGV. > > > True, but only when a path is passed in. If the default path is used, > looking up in the hash table is correct, and printing tracked aliases is > intentional. > > If it's desirable to drop that feature, then it should be dropped > completely, code shouldn't be left in that can no longer be used. But it's > possible to keep it working: how about this instead? > > Signed-off-by: Harald van Dijk <harald@gigawatt.nl> > --- > src/exec.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/src/exec.c b/src/exec.c > index ec0eadd..1350da3 100644 > --- a/src/exec.c > +++ b/src/exec.c > @@ -743,8 +743,6 @@ describe_command(out, command, path, verbose) > struct tblentry *cmdp; > const struct alias *ap; > > - path = path ?: pathval(); > - > if (verbose) { > outstr(command, out); > } > @@ -767,8 +765,15 @@ describe_command(out, command, path, verbose) > goto out; > } > > - /* Then check if it is a tracked alias */ > - if ((cmdp = cmdlookup(command, 0)) != NULL) { > + /* Then if the standard search path is used, check if it is a > tracked alias. */ > + if (path == NULL) { > + path = pathval(); > + cmdp = cmdlookup(command, 0); > + } else { > + cmdp = NULL; > + } > + > + if (cmdp != NULL) { > entry.cmdtype = cmdp->cmdtype; > entry.u = cmdp->param; > } else { -- To unsubscribe from this list: send the line "unsubscribe dash" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 26, 2017 at 09:59:44AM +0200, Harald van Dijk wrote: > Hi, > > On 26/05/17 09:04, Youfu Zhang wrote: > > $ PATH=/extra/path:/usr/sbin:/usr/bin:/sbin:/bin \ > >> sh -xc 'command -V ls; command -V ls; command -Vp ls; command -vp ls' > > + command -V ls > > ls is /bin/ls > > + command -V ls > > ls is a tracked alias for /bin/ls > > + command -Vp ls > > ls is a tracked alias for (null) > > + command -vp ls > > Segmentation fault (core dumped) > > > > describe_command should respect `path' argument. Looking up in the hash table > > may gives incorrect index in entry.u.index and finally causes incorrect output > > or SIGSEGV. > > True, but only when a path is passed in. If the default path is used, > looking up in the hash table is correct, and printing tracked aliases is > intentional. > > If it's desirable to drop that feature, then it should be dropped > completely, code shouldn't be left in that can no longer be used. But > it's possible to keep it working: how about this instead? > > Signed-off-by: Harald van Dijk <harald@gigawatt.nl> Patch applied. Thanks.
diff --git a/src/exec.c b/src/exec.c index ec0eadd..1350da3 100644 --- a/src/exec.c +++ b/src/exec.c @@ -743,8 +743,6 @@ describe_command(out, command, path, verbose) struct tblentry *cmdp; const struct alias *ap; - path = path ?: pathval(); - if (verbose) { outstr(command, out); } @@ -767,8 +765,15 @@ describe_command(out, command, path, verbose) goto out; } - /* Then check if it is a tracked alias */ - if ((cmdp = cmdlookup(command, 0)) != NULL) { + /* Then if the standard search path is used, check if it is a tracked alias. */ + if (path == NULL) { + path = pathval(); + cmdp = cmdlookup(command, 0); + } else { + cmdp = NULL; + } + + if (cmdp != NULL) { entry.cmdtype = cmdp->cmdtype; entry.u = cmdp->param;