Commit 03a8f3ab authored by Peng Fan's avatar Peng Fan Committed by Khalid Elmously

regmap: debugfs: check count when read regmap file

BugLink: https://bugs.launchpad.net/bugs/1889928

commit 74edd08a upstream.

When executing the following command, we met kernel dump.
dmesg -c > /dev/null; cd /sys;
for i in `ls /sys/kernel/debug/regmap/* -d`; do
	echo "Checking regmap in $i";
	cat $i/registers;
done && grep -ri "0x02d0" *;

It is because the count value is too big, and kmalloc fails. So add an
upper bound check to allow max size `PAGE_SIZE << (MAX_ORDER - 1)`.
Signed-off-by: default avatarPeng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1584064687-12964-1-git-send-email-peng.fan@nxp.comSigned-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
Signed-off-by: default avatarKhalid Elmously <khalid.elmously@canonical.com>
parent d2b56d7c
...@@ -194,6 +194,9 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, ...@@ -194,6 +194,9 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
if (*ppos < 0 || !count) if (*ppos < 0 || !count)
return -EINVAL; return -EINVAL;
if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
count = PAGE_SIZE << (MAX_ORDER - 1);
buf = kmalloc(count, GFP_KERNEL); buf = kmalloc(count, GFP_KERNEL);
if (!buf) if (!buf)
return -ENOMEM; return -ENOMEM;
...@@ -342,6 +345,9 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file, ...@@ -342,6 +345,9 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
if (*ppos < 0 || !count) if (*ppos < 0 || !count)
return -EINVAL; return -EINVAL;
if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
count = PAGE_SIZE << (MAX_ORDER - 1);
buf = kmalloc(count, GFP_KERNEL); buf = kmalloc(count, GFP_KERNEL);
if (!buf) if (!buf)
return -ENOMEM; return -ENOMEM;
......
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