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-rw-r--r--security/sandbox/linux/launch/SandboxLaunch.cpp25
1 files changed, 23 insertions, 2 deletions
diff --git a/security/sandbox/linux/launch/SandboxLaunch.cpp b/security/sandbox/linux/launch/SandboxLaunch.cpp
index bec94f3c4c..6617ff475d 100644
--- a/security/sandbox/linux/launch/SandboxLaunch.cpp
+++ b/security/sandbox/linux/launch/SandboxLaunch.cpp
@@ -511,6 +511,8 @@ static pid_t ForkWithFlags(int aFlags) {
return ret;
}
+// Returns true for success, or returns false and sets errno on
+// failure. Intended only for procfs pseudo-files.
static bool WriteStringToFile(const char* aPath, const char* aStr,
const size_t aLen) {
int fd = open(aPath, O_WRONLY);
@@ -519,6 +521,11 @@ static bool WriteStringToFile(const char* aPath, const char* aStr,
}
ssize_t written = write(fd, aStr, aLen);
if (close(fd) != 0 || written != ssize_t(aLen)) {
+ // procfs shouldn't ever cause a short write, but ensure that
+ // errno is set to something distinctive if it does
+ if (written >= 0) {
+ errno = EMSGSIZE;
+ }
return false;
}
return true;
@@ -537,6 +544,7 @@ static void ConfigureUserNamespace(uid_t uid, gid_t gid) {
len = static_cast<size_t>(SafeSPrintf(buf, "%d %d 1", uid, uid));
MOZ_RELEASE_ASSERT(len < sizeof(buf));
if (!WriteStringToFile("/proc/self/uid_map", buf, len)) {
+ SANDBOX_LOG_ERRNO("writing /proc/self/uid_map");
MOZ_CRASH("Failed to write /proc/self/uid_map");
}
@@ -549,6 +557,7 @@ static void ConfigureUserNamespace(uid_t uid, gid_t gid) {
len = static_cast<size_t>(SafeSPrintf(buf, "%d %d 1", gid, gid));
MOZ_RELEASE_ASSERT(len < sizeof(buf));
if (!WriteStringToFile("/proc/self/gid_map", buf, len)) {
+ SANDBOX_LOG_ERRNO("writing /proc/self/gid_map");
MOZ_CRASH("Failed to write /proc/self/gid_map");
}
}
@@ -641,6 +650,9 @@ void SandboxLaunch::StartChrootServer() {
char msg;
ssize_t msgLen = HANDLE_EINTR(read(mChrootServer, &msg, 1));
+ if (msgLen < 0) {
+ SANDBOX_LOG_ERRNO("chroot server couldn't read request");
+ }
if (msgLen == 0) {
// Process exited before chrooting (or chose not to chroot?).
_exit(0);
@@ -653,7 +665,10 @@ void SandboxLaunch::StartChrootServer() {
// exits at the end of this function, and which is always
// unwriteable.
int rv = chroot("/proc/self/fdinfo");
- MOZ_RELEASE_ASSERT(rv == 0);
+ if (rv != 0) {
+ SANDBOX_LOG_ERRNO("chroot");
+ MOZ_CRASH("chroot failed");
+ }
// Drop CAP_SYS_CHROOT ASAP. This must happen before responding;
// the main child won't be able to waitpid(), so it could start
@@ -664,10 +679,16 @@ void SandboxLaunch::StartChrootServer() {
// remove that. (Note: if the process can obtain directory fds, for
// example via SandboxBroker, it must be blocked from using fchdir.)
rv = chdir("/");
- MOZ_RELEASE_ASSERT(rv == 0);
+ if (rv != 0) {
+ SANDBOX_LOG_ERRNO("chdir(\"/\")");
+ MOZ_CRASH("chdir(\"/\") failed");
+ }
msg = kSandboxChrootResponse;
msgLen = HANDLE_EINTR(write(mChrootServer, &msg, 1));
+ if (msgLen < 0) {
+ SANDBOX_LOG_ERRNO("chroot server couldn't send response");
+ }
MOZ_RELEASE_ASSERT(msgLen == 1);
_exit(0);
}