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=== Description (from pull-request) ===
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
From 07f89c1e0e0718971e56189a71caafb35b046cab Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Fri, 26 Jun 2020 10:08:32 +0200
Subject: [PATCH] confile: handle overflow in lxc.time.offset.{boot,monotonic}
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
src/lxc/confile.c | 56 +++++++++++++++++++++++++++--------------------
src/lxc/utils.c | 12 ++++++++++
src/lxc/utils.h | 2 ++
3 files changed, 46 insertions(+), 24 deletions(-)
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index c92e19820d..75587d0ac8 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -2831,22 +2831,26 @@ static int set_config_time_offset_boot(const char *key,
const char *value,
if (ret)
return ret;
- /* TODO: Handle overflow. */
unit = lxc_trim_whitespace_in_place(buf);
- if (strcmp(unit, "h") == 0)
- lxc_conf->timens.s_boot = offset * 3600;
- else if (strcmp(unit, "m") == 0)
- lxc_conf->timens.s_boot = offset * 60;
- else if (strcmp(unit, "s") == 0)
+ if (strcmp(unit, "h") == 0) {
+ if (!multiply_overflow(offset, 3600, &lxc_conf->timens.s_boot))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "m") == 0) {
+ if (!multiply_overflow(offset, 60, &lxc_conf->timens.s_boot))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "s") == 0) {
lxc_conf->timens.s_boot = offset;
- else if (strcmp(unit, "ms") == 0)
- lxc_conf->timens.ns_boot = offset * 1000000;
- else if (strcmp(unit, "us") == 0)
- lxc_conf->timens.ns_boot = offset * 1000;
- else if (strcmp(unit, "ns") == 0)
+ } else if (strcmp(unit, "ms") == 0) {
+ if (!multiply_overflow(offset, 1000000,
&lxc_conf->timens.ns_boot))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "us") == 0) {
+ if (!multiply_overflow(offset, 1000, &lxc_conf->timens.ns_boot))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "ns") == 0) {
lxc_conf->timens.ns_boot = offset;
- else
+ } else {
return ret_errno(EINVAL);
+ }
return 0;
}
@@ -2866,22 +2870,26 @@ static int set_config_time_offset_monotonic(const char
*key, const char *value,
if (ret)
return ret;
- // TODO: Handle overflow.
unit = lxc_trim_whitespace_in_place(buf);
- if (strcmp(unit, "h") == 0)
- lxc_conf->timens.s_monotonic = offset * 3600;
- else if (strcmp(unit, "m") == 0)
- lxc_conf->timens.s_monotonic = offset * 60;
- else if (strcmp(unit, "s") == 0)
+ if (strcmp(unit, "h") == 0) {
+ if (!multiply_overflow(offset, 3600,
&lxc_conf->timens.s_monotonic))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "m") == 0) {
+ if (!multiply_overflow(offset, 60,
&lxc_conf->timens.s_monotonic))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "s") == 0) {
lxc_conf->timens.s_monotonic = offset;
- else if (strcmp(unit, "ms") == 0)
- lxc_conf->timens.ns_monotonic = offset * 1000000;
- else if (strcmp(unit, "us") == 0)
- lxc_conf->timens.ns_monotonic = offset * 1000;
- else if (strcmp(unit, "ns") == 0)
+ } else if (strcmp(unit, "ms") == 0) {
+ if (!multiply_overflow(offset, 1000000,
&lxc_conf->timens.ns_monotonic))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "us") == 0) {
+ if (!multiply_overflow(offset, 1000,
&lxc_conf->timens.ns_monotonic))
+ return -EOVERFLOW;
+ } else if (strcmp(unit, "ns") == 0) {
lxc_conf->timens.ns_monotonic = offset;
- else
+ } else {
return ret_errno(EINVAL);
+ }
return 0;
}
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 88d0f85ee5..cb7ca1d887 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1904,3 +1904,15 @@ int fix_stdio_permissions(uid_t uid)
return fret;
}
+
+bool multiply_overflow(int64_t base, uint64_t mult, int64_t *res)
+{
+ if (base > 0 && base > (INT64_MAX / mult))
+ return false;
+
+ if (base < 0 && base < (INT64_MIN / mult))
+ return false;
+
+ *res = base * mult;
+ return true;
+}
diff --git a/src/lxc/utils.h b/src/lxc/utils.h
index cf2c04251b..8c0e0c4aa5 100644
--- a/src/lxc/utils.h
+++ b/src/lxc/utils.h
@@ -251,4 +251,6 @@ static inline bool gid_valid(gid_t gid)
return gid != LXC_INVALID_GID;
}
+extern bool multiply_overflow(int64_t base, uint64_t mult, int64_t *res);
+
#endif /* __LXC_UTILS_H */
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