commit 867fe40f91b849393b56109586d85e499a53a142 Author: teor teor2345@gmail.com Date: Wed May 2 22:33:21 2018 +1000

Stop logging stack contents when reading a zero-length bandwidth file

When directory authorities read a zero-byte bandwidth file, they log a warning with the contents of an uninitialised buffer. Log a warning about the empty file instead.

Fixes bug 26007; bugfix on 0.2.2.1-alpha. --- changes/bug26007 | 5 +++++ src/or/dirserv.c | 13 +++++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/changes/bug26007 b/changes/bug26007 new file mode 100644 index 000000000..efcd15084 --- /dev/null +++ b/changes/bug26007 @@ -0,0 +1,5 @@ + o Major bugfixes (directory authorities, security): + - When directory authorities read a zero-byte bandwidth file, they log + a warning with the contents of an uninitialised buffer. Log a warning + about the empty file instead. + Fixes bug 26007; bugfix on 0.2.2.1-alpha. diff --git a/src/or/dirserv.c b/src/or/dirserv.c index 41c6bf3dc..94290d5dd 100644 --- a/src/or/dirserv.c +++ b/src/or/dirserv.c @@ -2750,14 +2750,23 @@ dirserv_read_measured_bandwidths(const char *from_file, time_t file_time, now; int ok;

+ /* Initialise line, so that we can't possibly run off the end. */ + memset(line, 0, sizeof(line)); + if (fp == NULL) { log_warn(LD_CONFIG, "Can't open bandwidth file at configured location: %s", from_file); return -1; }

- if (!fgets(line, sizeof(line), fp) - || !strlen(line) || line[strlen(line)-1] != '\n') { + /* If fgets fails, line is either unmodified, or indeterminate. */ + if (!fgets(line, sizeof(line), fp)) { + log_warn(LD_DIRSERV, "Empty bandwidth file"); + fclose(fp); + return -1; + } + + if (!strlen(line) || line[strlen(line)-1] != '\n') { log_warn(LD_DIRSERV, "Long or truncated time in bandwidth file: %s", escaped(line)); fclose(fp);