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import: drop all capabilities when invoking tar

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This commit is contained in:
Lennart Poettering
2015-01-22 18:12:31 +01:00
parent a8683176ee
commit 2c140ded48
4 changed files with 87 additions and 105 deletions
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src/import/import-common.c
+79
View File
@@ -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;
}
src/import/import-common.h
+2
View File
@@ -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);
src/import/import-dkr.c
+3 -53
View File
@@ -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;
}
src/import/import-tar.c
+3 -52
View File
@@ -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;
}