From a3d71f256c8a8b5d51ea0dfd09cd85ce3a09d9e1 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 15 May 2018 15:23:16 -0400 Subject: [PATCH] media: cec-pin-error-inj: avoid a false-positive Spectre detection The current logic makes Smatch to false-detect a Spectre variant 1 vulnerability. The problem is that it initializes an u32 indirectly from user space input. After trying to write a fixup, after a while I realized that, in practice, this shouldn't be a problem, as an u32 is initialized from u8, but it took some time to discover it. So, do some code cleanup to make it clearer for both humans and machines about the valid range for "op". Fix this warning: drivers/media/cec/cec-pin-error-inj.c:170 cec_pin_error_inj_parse_line() warn: potential spectre issue 'pin->error_inj_args' Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/cec/cec-pin-error-inj.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/media/cec/cec-pin-error-inj.c b/drivers/media/cec/cec-pin-error-inj.c index 7132a27..c0088d3 100644 --- a/drivers/media/cec/cec-pin-error-inj.c +++ b/drivers/media/cec/cec-pin-error-inj.c @@ -81,10 +81,9 @@ bool cec_pin_error_inj_parse_line(struct cec_adapter *adap, char *line) u64 *error; u8 *args; bool has_op; - u32 op; + u8 op; u8 mode; u8 pos; - u8 v; p = skip_spaces(p); token = strsep(&p, delims); @@ -146,12 +145,18 @@ bool cec_pin_error_inj_parse_line(struct cec_adapter *adap, char *line) comma = strchr(token, ','); if (comma) *comma++ = '\0'; - if (!strcmp(token, "any")) - op = CEC_ERROR_INJ_OP_ANY; - else if (!kstrtou8(token, 0, &v)) - op = v; - else + if (!strcmp(token, "any")) { + has_op = false; + error = pin->error_inj + CEC_ERROR_INJ_OP_ANY; + args = pin->error_inj_args[CEC_ERROR_INJ_OP_ANY]; + } else if (!kstrtou8(token, 0, &op)) { + has_op = true; + error = pin->error_inj + op; + args = pin->error_inj_args[op]; + } else { return false; + } + mode = CEC_ERROR_INJ_MODE_ONCE; if (comma) { if (!strcmp(comma, "off")) @@ -166,10 +171,6 @@ bool cec_pin_error_inj_parse_line(struct cec_adapter *adap, char *line) return false; } - error = pin->error_inj + op; - args = pin->error_inj_args[op]; - has_op = op <= 0xff; - token = strsep(&p, delims); if (p) { p = skip_spaces(p); -- 2.7.4