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Groups > linux.kernel > #1526370 > unrolled thread
| Started by | Oleg Drokin <green@linuxhacker.ru> |
|---|---|
| First post | 2016-11-21 06:50 +0100 |
| Last post | 2016-11-21 11:20 +0100 |
| Articles | 2 — 2 participants |
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[PATCH] staging/lustre: Use proper number of bytes in copy_from_user Oleg Drokin <green@linuxhacker.ru> - 2016-11-21 06:50 +0100
Re: [PATCH] staging/lustre: Use proper number of bytes in copy_from_user Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-21 11:20 +0100
| From | Oleg Drokin <green@linuxhacker.ru> |
|---|---|
| Date | 2016-11-21 06:50 +0100 |
| Subject | [PATCH] staging/lustre: Use proper number of bytes in copy_from_user |
| Message-ID | <sFPEl-5rv-1@gated-at.bofh.it> |
From: Jian Yu <jian.yu@intel.com> This patch removes the usage of MAX_STRING_SIZE from copy_from_user() and just copies enough bytes to cover count passed in. Signed-off-by: Jian Yu <jian.yu@intel.com> Reviewed-on: http://review.whamcloud.com/23462 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8774 Reviewed-by: John L. Hammond <john.hammond@intel.com> Signed-off-by: Oleg Drokin <green@linuxhacker.ru> --- drivers/staging/lustre/lustre/obdclass/lprocfs_status.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c index 8a2f02f3..db49992 100644 --- a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c +++ b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c @@ -400,10 +400,17 @@ int lprocfs_wr_uint(struct file *file, const char __user *buffer, char dummy[MAX_STRING_SIZE + 1], *end; unsigned long tmp; - dummy[MAX_STRING_SIZE] = '\0'; - if (copy_from_user(dummy, buffer, MAX_STRING_SIZE)) + if (count >= sizeof(dummy)) + return -EINVAL; + + if (count == 0) + return 0; + + if (copy_from_user(dummy, buffer, count)) return -EFAULT; + dummy[count] = '\0'; + tmp = simple_strtoul(dummy, &end, 0); if (dummy == end) return -EINVAL; -- 2.7.4
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| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Date | 2016-11-21 11:20 +0100 |
| Subject | Re: [PATCH] staging/lustre: Use proper number of bytes in copy_from_user |
| Message-ID | <sFTRD-8lZ-19@gated-at.bofh.it> |
| In reply to | #1526370 |
On Mon, Nov 21, 2016 at 12:46:48AM -0500, Oleg Drokin wrote: > From: Jian Yu <jian.yu@intel.com> > > This patch removes the usage of MAX_STRING_SIZE from > copy_from_user() and just copies enough bytes to cover > count passed in. > > Signed-off-by: Jian Yu <jian.yu@intel.com> > Reviewed-on: http://review.whamcloud.com/23462 > Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8774 > Reviewed-by: John L. Hammond <john.hammond@intel.com> > Signed-off-by: Oleg Drokin <green@linuxhacker.ru> > --- > drivers/staging/lustre/lustre/obdclass/lprocfs_status.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c > index 8a2f02f3..db49992 100644 > --- a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c > +++ b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c > @@ -400,10 +400,17 @@ int lprocfs_wr_uint(struct file *file, const char __user *buffer, > char dummy[MAX_STRING_SIZE + 1], *end; > unsigned long tmp; > > - dummy[MAX_STRING_SIZE] = '\0'; > - if (copy_from_user(dummy, buffer, MAX_STRING_SIZE)) > + if (count >= sizeof(dummy)) > + return -EINVAL; > + > + if (count == 0) > + return 0; > + > + if (copy_from_user(dummy, buffer, count)) > return -EFAULT; > > + dummy[count] = '\0'; > + You do know about simple_read_from_buffer(), right? I suggest using those simple_* functions where ever you are touching user buffers, like this code. thanks, greg k-h
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