Skip to content

main: wipe SSH password/passphrase from environment memory #46

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
acts-1631 wants to merge 1 commit into
base: main
Choose a base branch
from
Open

main: wipe SSH password/passphrase from environment memory #46

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 25 additions & 0 deletions src/main.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
Expand Down Expand Up @@ -483,8 +484,32 @@ int main(int argc, char **argv)
if (quiet)
to_dev_null(STDOUT_FILENO);

/* Snapshot password/passphrase from the environment, then wipe
* them in place. getenv() returns a pointer directly into the
* process's original environment block, which stays readable by
* any local process with the same uid via /proc/PID/environ for
* as long as the bytes remain unmodified -- calling unsetenv()
* alone does NOT clear this, since /proc/PID/environ reflects
* the raw exec-time memory, not libc's environ[] bookkeeping.
* Copy the value to the heap, then memset the original bytes to
* remove them from that memory, keeping non-interactive usage
* (scripts, CI) working without leaving the secret exposed for
* the remaining lifetime of the process.
*/
s.password = getenv(ENV_SSH_AUTH_PASSWORD);
s.passphrase = getenv(ENV_SSH_AUTH_PASSPHRASE);
if (s.password) {
char *p = s.password;
s.password = strdup(p);
memset(p, 0, strlen(p));
}
if (s.passphrase) {
char *p = s.passphrase;
s.passphrase = strdup(p);
memset(p, 0, strlen(p));
}
unsetenv(ENV_SSH_AUTH_PASSWORD);
unsetenv(ENV_SSH_AUTH_PASSPHRASE);

if ((m = mscp_init(&o, &s)) == NULL) {
pr_err("mscp_init: %s", priv_get_err());
Expand Down