Commit d43918ae authored by Mark Brown's avatar Mark Brown Committed by Luis Henriques

regmap: debugfs: Ensure we don't underflow when printing access masks

commit b763ec17 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: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent e25b6baf
...@@ -432,7 +432,7 @@ static ssize_t regmap_access_read_file(struct file *file, ...@@ -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 we're in the region the user is trying to read */
if (p >= *ppos) { if (p >= *ppos) {
/* ...but not beyond it */ /* ...but not beyond it */
if (buf_pos >= count - 1 - tot_len) if (buf_pos + tot_len + 1 >= count)
break; break;
/* Format the register */ /* Format the register */
......
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