From: Dan Carpenter <dan.carpenter@oracle.com> To: Jan Harkes <jaharkes@cs.cmu.edu> Cc: coda@cs.cmu.edu, codalist@telemann.coda.cs.cmu.edu, linux-fsdevel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] fs/coda: potential buffer overflow in coda_psdev_write() Date: Thu, 12 Jul 2018 15:32:56 +0300 [thread overview] Message-ID: <20180712123255.rkcszmwdmrloxaki@kili.mountain> (raw) "dcbuf" is a union that is "size" bytes large. We ensure that "nbytes" is large enough to hold the smallest member of the union, but if we require a larger union member then then we could access beyond the end of the allocated memory in coda_downcall(). The union is quite small so we can allocate enough space so everything fits. The CODA_ALLOC() macro calls kzalloc() which means the extra memory is just zeroed and it's fine. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index c5234c21b539..910d57e576e2 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -124,7 +124,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, hdr.opcode, hdr.unique); nbytes = size; } - CODA_ALLOC(dcbuf, union outputArgs *, nbytes); + CODA_ALLOC(dcbuf, union outputArgs *, size); if (copy_from_user(dcbuf, buf, nbytes)) { CODA_FREE(dcbuf, nbytes); retval = -EFAULT;
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com> To: Jan Harkes <jaharkes@cs.cmu.edu> Cc: coda@cs.cmu.edu, codalist@telemann.coda.cs.cmu.edu, linux-fsdevel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] fs/coda: potential buffer overflow in coda_psdev_write() Date: Thu, 12 Jul 2018 12:32:56 +0000 [thread overview] Message-ID: <20180712123255.rkcszmwdmrloxaki@kili.mountain> (raw) "dcbuf" is a union that is "size" bytes large. We ensure that "nbytes" is large enough to hold the smallest member of the union, but if we require a larger union member then then we could access beyond the end of the allocated memory in coda_downcall(). The union is quite small so we can allocate enough space so everything fits. The CODA_ALLOC() macro calls kzalloc() which means the extra memory is just zeroed and it's fine. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index c5234c21b539..910d57e576e2 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -124,7 +124,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, hdr.opcode, hdr.unique); nbytes = size; } - CODA_ALLOC(dcbuf, union outputArgs *, nbytes); + CODA_ALLOC(dcbuf, union outputArgs *, size); if (copy_from_user(dcbuf, buf, nbytes)) { CODA_FREE(dcbuf, nbytes); retval = -EFAULT;
next reply other threads:[~2018-07-12 12:43 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-07-12 12:32 Dan Carpenter [this message] 2018-07-12 12:32 ` [PATCH] fs/coda: potential buffer overflow in coda_psdev_write() Dan Carpenter 2018-07-12 15:31 ` Jan Harkes 2018-07-12 15:31 ` Jan Harkes 2018-07-12 15:50 ` Dan Carpenter 2018-07-12 15:50 ` Dan Carpenter 2018-07-13 15:10 ` [PATCH v2] " Dan Carpenter 2018-07-13 16:16 ` Jan Harkes 2018-07-13 19:05 ` Dan Carpenter 2018-07-13 19:05 ` Dan Carpenter 2018-07-13 19:08 ` Jan Harkes 2018-07-13 19:08 ` Jan Harkes 2018-07-14 2:24 ` [PATCH v3] " Jan Harkes 2018-07-14 2:24 ` Jan Harkes
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180712123255.rkcszmwdmrloxaki@kili.mountain \ --to=dan.carpenter@oracle.com \ --cc=coda@cs.cmu.edu \ --cc=codalist@telemann.coda.cs.cmu.edu \ --cc=jaharkes@cs.cmu.edu \ --cc=kernel-janitors@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.