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loop: use sysfs_emit() in the sysfs xxx show()

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[ Upstream commit b27824d31f09ea7b4a6ba2c1b18bd328df3e8bed ]

sprintf does not know the PAGE_SIZE maximum of the temporary buffer
used for outputting sysfs content and it's possible to overrun the
PAGE_SIZE buffer length.

Use a generic sysfs_emit function that knows the size of the
temporary buffer and ensures that no overrun is done for offset
attribute in
loop_attr_[offset|sizelimit|autoclear|partscan|dio]_show() callbacks.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Link: https://lore.kernel.org/r/20220215213310.7264-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chaitanya Kulkarni 2022-02-15 13:33:07 -08:00 committed by Greg Kroah-Hartman
parent 448857f580
commit 012c572007
1 changed files with 5 additions and 5 deletions
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10
drivers/block/loop.c
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@ -797,33 +797,33 @@ static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
{
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
return sysfs_emit(buf, "%llu\n", (unsigned long long)lo->lo_offset);
}
static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
{
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
return sysfs_emit(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
}
static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf)
{
int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR);
return sprintf(buf, "%s\n", autoclear ? "1" : "0");
return sysfs_emit(buf, "%s\n", autoclear ? "1" : "0");
}
static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
{
int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
return sprintf(buf, "%s\n", partscan ? "1" : "0");
return sysfs_emit(buf, "%s\n", partscan ? "1" : "0");
}
static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf)
{
int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO);
return sprintf(buf, "%s\n", dio ? "1" : "0");
return sysfs_emit(buf, "%s\n", dio ? "1" : "0");
}
LOOP_ATTR_RO(backing_file);