From: Mark Brown Date: Sat, 19 Sep 2015 14:00:18 +0000 (-0700) Subject: regmap: debugfs: Ensure we don't underflow when printing access masks X-Git-Tag: v4.2.4~72 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=08098bda6e983029027548e16a6e796cefa992dc;p=thirdparty%2Fkernel%2Fstable.git regmap: debugfs: Ensure we don't underflow when printing access masks commit b763ec17ac762470eec5be8ebcc43e4f8b2c2b82 upstream. If a read is attempted which is smaller than the line length then we may underflow the subtraction we're doing with the unsigned size_t type so move some of the calculation to be additions on the right hand side instead in order to avoid this. Reported-by: Rasmus Villemoes Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 5799a0b9e6cc4..1f6cd1583a809 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -432,7 +432,7 @@ static ssize_t regmap_access_read_file(struct file *file, /* If we're in the region the user is trying to read */ if (p >= *ppos) { /* ...but not beyond it */ - if (buf_pos >= count - 1 - tot_len) + if (buf_pos + tot_len + 1 >= count) break; /* Format the register */