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authorLennart Poettering <lennart@poettering.net>2015-01-22 18:12:31 +0100
committerLennart Poettering <lennart@poettering.net>2015-01-22 18:12:31 +0100
commit2c140ded48fc31e3c80a92a1f755a2b1ab6e1a30 (patch)
tree2cccd6b80ceabdeb2fb45db05e830bc89d99e074
parenta8683176ee1da908c65721468141a74892791fda (diff)
import: drop all capabilities when invoking tar
-rw-r--r--src/import/import-common.c79
-rw-r--r--src/import/import-common.h2
-rw-r--r--src/import/import-dkr.c56
-rw-r--r--src/import/import-tar.c55
4 files changed, 87 insertions, 105 deletions
diff --git a/src/import/import-common.c b/src/import/import-common.c
index 561c77abdf..b490c435d2 100644
--- a/src/import/import-common.c
+++ b/src/import/import-common.c
@@ -25,6 +25,7 @@
#include "strv.h"
#include "copy.h"
#include "btrfs-util.h"
+#include "capability.h"
#include "import-job.h"
#include "import-common.h"
@@ -447,3 +448,81 @@ finish:
return r;
}
+
+int import_fork_tar(const char *path, pid_t *ret) {
+ _cleanup_close_pair_ int pipefd[2] = { -1, -1 };
+ pid_t pid;
+ int r;
+
+ assert(path);
+ assert(ret);
+
+ if (pipe2(pipefd, O_CLOEXEC) < 0)
+ return log_error_errno(errno, "Failed to create pipe for tar: %m");
+
+ pid = fork();
+ if (pid < 0)
+ return log_error_errno(errno, "Failed to fork off tar: %m");
+
+ if (pid == 0) {
+ int null_fd;
+ uint64_t retain =
+ (1ULL << CAP_CHOWN) |
+ (1ULL << CAP_FOWNER) |
+ (1ULL << CAP_FSETID) |
+ (1ULL << CAP_MKNOD) |
+ (1ULL << CAP_SETFCAP);
+
+ /* Child */
+
+ reset_all_signal_handlers();
+ reset_signal_mask();
+ assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
+
+ pipefd[1] = safe_close(pipefd[1]);
+
+ if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
+ log_error_errno(errno, "Failed to dup2() fd: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (pipefd[0] != STDIN_FILENO)
+ pipefd[0] = safe_close(pipefd[0]);
+
+ null_fd = open("/dev/null", O_WRONLY|O_NOCTTY);
+ if (null_fd < 0) {
+ log_error_errno(errno, "Failed to open /dev/null: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) {
+ log_error_errno(errno, "Failed to dup2() fd: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (null_fd != STDOUT_FILENO)
+ null_fd = safe_close(null_fd);
+
+ fd_cloexec(STDIN_FILENO, false);
+ fd_cloexec(STDOUT_FILENO, false);
+ fd_cloexec(STDERR_FILENO, false);
+
+ r = capability_bounding_set_drop(~retain, true);
+ if (r < 0) {
+ log_error_errno(errno, "Failed to drop capabilities, ignoring: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ execlp("tar", "tar", "--numeric-owner", "-C", path, "-px", NULL);
+ log_error_errno(errno, "Failed to execute tar: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ pipefd[0] = safe_close(pipefd[0]);
+ r = pipefd[1];
+ pipefd[1] = -1;
+
+ *ret = pid;
+
+ return r;
+}
diff --git a/src/import/import-common.h b/src/import/import-common.h
index 39ac6acd08..f6b4268fd7 100644
--- a/src/import/import-common.h
+++ b/src/import/import-common.h
@@ -37,3 +37,5 @@ int import_make_path(const char *url, const char *etag, const char *image_root,
int import_make_verification_jobs(ImportJob **ret_checksum_job, ImportJob **ret_signature_job, ImportVerify verify, const char *url, CurlGlue *glue, ImportJobFinished on_finished, void *userdata);
int import_verify(ImportJob *main_job, ImportJob *checksum_job, ImportJob *signature_job);
+
+int import_fork_tar(const char *path, pid_t *ret);
diff --git a/src/import/import-dkr.c b/src/import/import-dkr.c
index 0e99275090..24ba766b13 100644
--- a/src/import/import-dkr.c
+++ b/src/import/import-dkr.c
@@ -401,7 +401,6 @@ static int dkr_import_make_local_copy(DkrImport *i) {
}
static int dkr_import_job_on_open_disk(ImportJob *j) {
- _cleanup_close_pair_ int pipefd[2] = { -1, -1 };
const char *base;
DkrImport *i;
int r;
@@ -432,58 +431,9 @@ static int dkr_import_job_on_open_disk(ImportJob *j) {
if (r < 0)
return log_error_errno(r, "Failed to make btrfs subvolume %s: %m", i->temp_path);
- if (pipe2(pipefd, O_CLOEXEC) < 0)
- return log_error_errno(errno, "Failed to create pipe for tar: %m");
-
- i->tar_pid = fork();
- if (i->tar_pid < 0)
- return log_error_errno(errno, "Failed to fork off tar: %m");
- if (i->tar_pid == 0) {
- int null_fd;
-
- /* Child */
-
- reset_all_signal_handlers();
- reset_signal_mask();
- assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
-
- pipefd[1] = safe_close(pipefd[1]);
-
- if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
- log_error_errno(errno, "Failed to dup2() fd: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (pipefd[0] != STDIN_FILENO)
- pipefd[0] = safe_close(pipefd[0]);
-
- null_fd = open("/dev/null", O_WRONLY|O_NOCTTY);
- if (null_fd < 0) {
- log_error_errno(errno, "Failed to open /dev/null: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) {
- log_error_errno(errno, "Failed to dup2() fd: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (null_fd != STDOUT_FILENO)
- null_fd = safe_close(null_fd);
-
- fd_cloexec(STDIN_FILENO, false);
- fd_cloexec(STDOUT_FILENO, false);
- fd_cloexec(STDERR_FILENO, false);
-
- execlp("tar", "tar", "--numeric-owner", "-C", i->temp_path, "-px", NULL);
- log_error_errno(errno, "Failed to execute tar: %m");
- _exit(EXIT_FAILURE);
- }
-
- pipefd[0] = safe_close(pipefd[0]);
-
- j->disk_fd = pipefd[1];
- pipefd[1] = -1;
+ j->disk_fd = import_fork_tar(i->temp_path, &i->tar_pid);
+ if (j->disk_fd < 0)
+ return j->disk_fd;
return 0;
}
diff --git a/src/import/import-tar.c b/src/import/import-tar.c
index e311ad277f..80ae83971e 100644
--- a/src/import/import-tar.c
+++ b/src/import/import-tar.c
@@ -270,58 +270,9 @@ static int tar_import_job_on_open_disk(ImportJob *j) {
} else if (r < 0)
return log_error_errno(errno, "Failed to create subvolume %s: %m", i->temp_path);
- if (pipe2(pipefd, O_CLOEXEC) < 0)
- return log_error_errno(errno, "Failed to create pipe for tar: %m");
-
- i->tar_pid = fork();
- if (i->tar_pid < 0)
- return log_error_errno(errno, "Failed to fork off tar: %m");
- if (i->tar_pid == 0) {
- int null_fd;
-
- /* Child */
-
- reset_all_signal_handlers();
- reset_signal_mask();
- assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
-
- pipefd[1] = safe_close(pipefd[1]);
-
- if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
- log_error_errno(errno, "Failed to dup2() fd: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (pipefd[0] != STDIN_FILENO)
- pipefd[0] = safe_close(pipefd[0]);
-
- null_fd = open("/dev/null", O_WRONLY|O_NOCTTY);
- if (null_fd < 0) {
- log_error_errno(errno, "Failed to open /dev/null: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) {
- log_error_errno(errno, "Failed to dup2() fd: %m");
- _exit(EXIT_FAILURE);
- }
-
- if (null_fd != STDOUT_FILENO)
- null_fd = safe_close(null_fd);
-
- fd_cloexec(STDIN_FILENO, false);
- fd_cloexec(STDOUT_FILENO, false);
- fd_cloexec(STDERR_FILENO, false);
-
- execlp("tar", "tar", "--numeric-owner", "-C", i->temp_path, "-px", NULL);
- log_error_errno(errno, "Failed to execute tar: %m");
- _exit(EXIT_FAILURE);
- }
-
- pipefd[0] = safe_close(pipefd[0]);
-
- j->disk_fd = pipefd[1];
- pipefd[1] = -1;
+ j->disk_fd = import_fork_tar(i->temp_path, &i->tar_pid);
+ if (j->disk_fd < 0)
+ return j->disk_fd;
return 0;
}