Messages in this thread Patch in this message | | | From | Toshi Kani <> | Subject | [PATCH v2 2/2] EDAC: Fix sysfs dimm_label store operation | Date | Tue, 22 Sep 2015 08:58:03 -0600 |
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Sysfs "dimm_label" and "chX_dimm_label" have the following issues in their store operation.
1) A newline-terminated input string causes redundant newlines
# echo "test" > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label test
# od -bc /sys/bus/mc0/devices/dimm0/dimm_label 0000000 164 145 163 164 012 012 t e s t \n \n 0000006
2) The original label string (31 characters) cannot be stored due to an improper size check
# echo "CPU_SrcID#0_Ha#0_Chan#0_DIMM#0" \ > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label
# od -bc /sys/bus/mc0/devices/dimm0/dimm_label 0000000 012 012 \n \n 0000002
3) An input string longer than the buffer size results a wrong label info as it allows a retry with the remaining string.
# echo "CPU_SrcID#0_Ha#0_Chan#0_DIMM#0_TEST" \ > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label _TEST
Fix these issues by making the following changes: 1) Replace a newline charactor at the end by setting a null. It also assures that the string is null-terminated within the size. 2) Check the label buffer size with 'sizeof(dimm->label)'. 3) Fail a request if its string exceeds the label buffer size.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Acked-by: Tony Luck <tony.luck@intel.com> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Doug Thompson <dougthompson@xmission.com> Cc: Robert Elliott <elliott@hpe.com> Cc: Tony Luck <tony.luck@intel.com> --- drivers/edac/edac_mc_sysfs.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c index 8983755..01ad279 100644 --- a/drivers/edac/edac_mc_sysfs.c +++ b/drivers/edac/edac_mc_sysfs.c @@ -241,13 +241,13 @@ static ssize_t channel_dimm_label_store(struct device *dev, unsigned chan = to_channel(mattr); struct rank_info *rank = csrow->channels[chan]; - ssize_t max_size = 0; + if (count == 0 || count > sizeof(rank->dimm->label)) + return -EINVAL; - max_size = min((ssize_t) count, (ssize_t) EDAC_MC_LABEL_LEN - 1); - strncpy(rank->dimm->label, data, max_size); - rank->dimm->label[max_size] = '\0'; + strncpy(rank->dimm->label, data, count); + rank->dimm->label[count - 1] = '\0'; - return max_size; + return count; } /* show function for dynamic chX_ce_count attribute */ @@ -495,13 +495,13 @@ static ssize_t dimmdev_label_store(struct device *dev, { struct dimm_info *dimm = to_dimm(dev); - ssize_t max_size = 0; + if (count == 0 || count > sizeof(dimm->label)) + return -EINVAL; - max_size = min((ssize_t) count, (ssize_t) EDAC_MC_LABEL_LEN - 1); - strncpy(dimm->label, data, max_size); - dimm->label[max_size] = '\0'; + strncpy(dimm->label, data, count); + dimm->label[count - 1] = '\0'; - return max_size; + return count; } static ssize_t dimmdev_size_show(struct device *dev,
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