diff options
| author | Roy Marples <roy@marples.name> | 2020-09-12 20:14:47 +0100 |
|---|---|---|
| committer | Roy Marples <roy@marples.name> | 2020-09-12 20:14:47 +0100 |
| commit | c8509b2f956a2b580c448e0c8caddc1713511201 (patch) | |
| tree | ae5f697f5be1d7cdddfd2d255f3c042566332939 /src/privsep.c | |
| parent | 0251bd3eccf094ce8f32e700fa306fc5e8b0f9ce (diff) | |
| download | dhcpcd-c8509b2f956a2b580c448e0c8caddc1713511201.tar.xz | |
dhcpcd: Only manipulate stdin, stdout and stderr when valid
UNIX application expect these to exist even if pointed at /dev/null.
We cannot change which fd they use, it's always 0, 1 and 2.
But if these fd's are not open when dhcpcd is called, they could
be assigned to dhcpcd internals.
In this instance we should not use the streams in anyway or form.
Diffstat (limited to 'src/privsep.c')
| -rw-r--r-- | src/privsep.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/src/privsep.c b/src/privsep.c index 3f1dc2d6..f92ef45b 100644 --- a/src/privsep.c +++ b/src/privsep.c @@ -76,7 +76,6 @@ #ifdef HAVE_CAPSICUM #include <sys/capsicum.h> #include <capsicum_helpers.h> -#define ps_rights_limit_stdio caph_limit_stdio #endif #ifdef HAVE_UTIL_H #include <util.h> @@ -278,6 +277,25 @@ ps_rights_limit_fdpair(int fd[]) return -1; return 0; } + +static int +ps_rights_limit_stdio(struct dhcpcd_ctx *ctx) +{ + const int iebadf = CAPH_IGNORE_EBADF; + int error = 0; + + if (ctx->stdin_valid && + caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1) + error = -1; + if (ctx->stdout_valid && + caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1) + error = -1; + if (ctx->stderr_valid && + caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1) + error = -1; + + return error; +} #endif pid_t @@ -346,7 +364,7 @@ ps_dostart(struct dhcpcd_ctx *ctx, #ifdef PRIVSEP_RIGHTS /* We cannot limit the root process in any way. */ - if (ps_rights_limit_stdio() == -1) { + if (ps_rights_limit_stdio(ctx) == -1) { logerr("ps_rights_limit_stdio"); goto errexit; } @@ -484,7 +502,7 @@ ps_mastersandbox(struct dhcpcd_ctx *ctx) if ((ctx->pf_inet_fd != -1 && ps_rights_limit_ioctl(ctx->pf_inet_fd) == -1) || (ctx->link_fd != -1 && ps_rights_limit_fd(ctx->link_fd) == -1) || - ps_rights_limit_stdio() == -1) + ps_rights_limit_stdio(ctx) == -1) { logerr("%s: cap_rights_limit", __func__); return -1; |