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Refactor the sudoedit code to copy files so it can be shared.

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The SELinux sudoedit code now extends the destination file the
same way the non-SELinux version does.
This commit is contained in:
Todd C. Miller
2020-04-21 11:05:32 -06:00
parent 0bd39701b4
commit 009876bf36
6 changed files with 193 additions and 119 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
MANIFEST
View File

@@ -956,6 +956,7 @@ scripts/mkpkg
scripts/pp
src/Makefile.in
src/conversation.c
src/copy_file.c
src/env_hooks.c
src/exec.c
src/exec_common.c

27
src/Makefile.in
View File

@@ -123,16 +123,17 @@ SHELL = @SHELL@
PROGS = @PROGS@
OBJS = conversation.o env_hooks.o exec.o exec_common.o exec_monitor.o \
exec_nopty.o exec_pty.o get_pty.o hooks.o limits.o load_plugins.o \
net_ifs.o parse_args.o preserve_fds.o signal.o sudo.o sudo_edit.o \
tcsetpgrp_nobg.o tgetpass.o ttyname.o utmp.o @SUDO_OBJS@
OBJS = conversation.o copy_file.o env_hooks.o exec.o exec_common.o \
exec_monitor.o exec_nopty.o exec_pty.o get_pty.o hooks.o \
limits.o load_plugins.o net_ifs.o parse_args.o preserve_fds.o \
signal.o sudo.o sudo_edit.o tcsetpgrp_nobg.o tgetpass.o \
ttyname.o utmp.o @SUDO_OBJS@
IOBJS = $(OBJS:.o=.i) sesh.i
POBJS = $(IOBJS:.i=.plog)
SESH_OBJS = sesh.o exec_common.o
SESH_OBJS = copy_file.o exec_common.o sesh.o
CHECK_NOEXEC_OBJS = check_noexec.o exec_common.o
@@ -341,6 +342,22 @@ conversation.i: $(srcdir)/conversation.c $(incdir)/compat/stdbool.h \
$(CC) -E -o $@ $(CPPFLAGS) $<
conversation.plog: conversation.i
rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/conversation.c --i-file $< --output-file $@
copy_file.o: $(srcdir)/copy_file.c $(incdir)/compat/stdbool.h \
$(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
$(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
$(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
$(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/sudo.h \
$(top_builddir)/config.h $(top_builddir)/pathnames.h
$(CC) -c $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(SSP_CFLAGS) $(srcdir)/copy_file.c
copy_file.i: $(srcdir)/copy_file.c $(incdir)/compat/stdbool.h \
$(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
$(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
$(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
$(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/sudo.h \
$(top_builddir)/config.h $(top_builddir)/pathnames.h
$(CC) -E -o $@ $(CPPFLAGS) $<
copy_file.plog: copy_file.i
rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/copy_file.c --i-file $< --output-file $@
env_hooks.o: $(srcdir)/env_hooks.c $(incdir)/compat/stdbool.h \
$(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
$(incdir)/sudo_debug.h $(incdir)/sudo_dso.h \

128
src/copy_file.c Normal file
View File

@@ -0,0 +1,128 @@
/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "sudo.h"
/*
* Extend the given fd to the specified size in bytes.
* We do this to allocate disk space up-front before overwriting
* the original file with the temporary. Otherwise, we could
* we run out of disk space after truncating the original file.
*/
static int
sudo_extend_file(int fd, const char *name, off_t new_size)
{
off_t old_size, size;
ssize_t nwritten;
char zeroes[BUFSIZ] = { '\0' };
debug_decl(sudo_extend_file, SUDO_DEBUG_UTIL);
if ((old_size = lseek(fd, 0, SEEK_END)) == -1) {
sudo_warn("lseek");
debug_return_int(-1);
}
sudo_debug_printf(SUDO_DEBUG_INFO, "%s: extending %s from %lld to %lld",
__func__, name, (long long)old_size, (long long)new_size);
for (size = old_size; size < new_size; size += nwritten) {
size_t len = new_size - size;
if (len > sizeof(zeroes))
len = sizeof(zeroes);
nwritten = write(fd, zeroes, len);
if (nwritten == -1) {
int serrno = errno;
if (ftruncate(fd, old_size) == -1) {
sudo_debug_printf(
SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
"unable to truncate %s to %lld", name, (long long)old_size);
}
errno = serrno;
debug_return_int(-1);
}
}
if (lseek(fd, 0, SEEK_SET) == -1) {
sudo_warn("lseek");
debug_return_int(-1);
}
debug_return_int(0);
}
/*
* Copy the contents of src_fd into dst_fd.
* Returns 0 on success or -1 on error.
*/
int
sudo_copy_file(const char *src, int src_fd, off_t src_len, const char *dst,
int dst_fd, off_t dst_len)
{
char buf[BUFSIZ];
ssize_t nwritten, nread;
debug_decl(sudo_copy_file, SUDO_DEBUG_UTIL);
/* Extend the file to the new size if larger before copying. */
if (dst_len > 0 && src_len > dst_len) {
if (sudo_extend_file(dst_fd, dst, src_len) == -1)
goto write_error;
}
/* Overwrite the old file with the new contents. */
while ((nread = read(src_fd, buf, sizeof(buf))) > 0) {
ssize_t off = 0;
do {
nwritten = write(dst_fd, buf + off, nread - off);
if (nwritten == -1)
goto write_error;
off += nwritten;
} while (nread > off);
}
if (nread == 0) {
/* success, read to EOF */
if (src_len < dst_len) {
/* We don't open with O_TRUNC so must truncate manually. */
if (ftruncate(dst_fd, src_len) == -1) {
sudo_debug_printf(
SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
"unable to truncate %s to %lld", dst, (long long)src_len);
goto write_error;
}
}
debug_return_int(0);
} else if (nread < 0) {
sudo_warn(U_("unable to read from %s"), src);
debug_return_int(-1);
} else {
write_error:
sudo_warn(U_("unable to write to %s"), dst);
debug_return_int(-1);
}
}

37
src/sesh.c
View File

@@ -1,7 +1,7 @@
/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2008, 2010-2018 Todd C. Miller <Todd.Miller@sudo.ws>
* Copyright (c) 2008, 2010-2018, 2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@@ -136,10 +136,8 @@ sesh_sudoedit(int argc, char *argv[])
{
int i, oflags_dst, post, ret = SESH_ERR_FAILURE;
int fd_src = -1, fd_dst = -1, follow = 0;
ssize_t nread, nwritten;
struct stat sb;
struct timespec times[2];
char buf[BUFSIZ];
debug_decl(sesh_sudoedit, SUDO_DEBUG_EDIT);
/* Check for -h flag (don't follow links). */
@@ -182,7 +180,7 @@ sesh_sudoedit(int argc, char *argv[])
* so that it's ensured that the temporary files are
* created by us and that we are not opening any symlinks.
*/
oflags_dst = O_WRONLY|O_TRUNC|O_CREAT|(post ? follow : O_EXCL);
oflags_dst = O_WRONLY|O_CREAT|(post ? follow : O_EXCL);
for (i = 0; i < argc - 1; i += 2) {
const char *path_src = argv[i];
const char *path_dst = argv[i + 1];
@@ -214,14 +212,29 @@ sesh_sudoedit(int argc, char *argv[])
}
if (fd_src != -1) {
while ((nread = read(fd_src, buf, sizeof(buf))) > 0) {
if ((nwritten = write(fd_dst, buf, nread)) != nread) {
sudo_warn("%s", path_src);
if (post) {
ret = SESH_ERR_SOME_FILES;
goto nocleanup;
} else
goto cleanup_0;
off_t len_src = -1;
off_t len_dst = -1;
if (post) {
if (fstat(fd_src, &sb) != 0) {
ret = SESH_ERR_SOME_FILES;
goto nocleanup;
}
len_src = sb.st_size;
if (fstat(fd_dst, &sb) != 0) {
ret = SESH_ERR_SOME_FILES;
goto nocleanup;
}
len_dst = sb.st_size;
}
if (sudo_copy_file(path_src, fd_src, len_src, path_dst, fd_dst,
len_dst) == -1) {
if (post) {
ret = SESH_ERR_SOME_FILES;
goto nocleanup;
} else {
goto cleanup_0;
}
}
}

116
src/sudo_edit.c
View File

@@ -42,7 +42,6 @@
#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include "sudo.h"
@@ -532,8 +531,6 @@ sudo_edit_create_tfiles(struct command_details *command_details,
struct tempfile *tf, char *files[], int nfiles)
{
int i, j, tfd, ofd, rc;
char buf[BUFSIZ];
ssize_t nwritten, nread;
struct timespec times[2];
struct stat sb;
debug_decl(sudo_edit_create_tfiles, SUDO_DEBUG_EDIT);
@@ -610,18 +607,7 @@ sudo_edit_create_tfiles(struct command_details *command_details,
debug_return_int(-1);
}
if (ofd != -1) {
while ((nread = read(ofd, buf, sizeof(buf))) > 0) {
if ((nwritten = write(tfd, buf, nread)) != nread) {
if (nwritten == -1)
sudo_warn("%s", tf[j].tfile);
else
sudo_warnx(U_("%s: short write"), tf[j].tfile);
break;
}
}
if (nread != 0) {
if (nread < 0)
sudo_warn("%s", files[i]);
if (sudo_copy_file(tf[j].ofile, ofd, tf[j].osize, tf[j].tfile, tfd, -1) == -1) {
close(ofd);
close(tfd);
debug_return_int(-1);
@@ -650,51 +636,6 @@ sudo_edit_create_tfiles(struct command_details *command_details,
debug_return_int(j);
}
/*
* Extend the given fd to the specified size in bytes.
* We do this to allocate disk space up-front before overwriting
* the original file with the temporary. Otherwise, we could
* we run out of disk space after truncating the original file.
*/
static int
sudo_edit_extend_file(int fd, off_t new_size)
{
off_t old_size, size;
ssize_t nwritten;
char zeroes[1024] = { '\0' };
debug_decl(sudo_edit_extend_file, SUDO_DEBUG_EDIT);
if ((old_size = lseek(fd, 0, SEEK_END)) == -1) {
sudo_warn("lseek");
debug_return_int(-1);
}
sudo_debug_printf(SUDO_DEBUG_INFO, "%s: extending file from %lld to %lld",
__func__, (long long)old_size, (long long)new_size);
for (size = old_size; size < new_size; size += nwritten) {
size_t len = new_size - size;
if (len > sizeof(zeroes))
len = sizeof(zeroes);
nwritten = write(fd, zeroes, len);
if (nwritten == -1) {
int serrno = errno;
if (ftruncate(fd, old_size) == -1) {
sudo_debug_printf(
SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
"unable to truncate to %lld", (long long)old_size);
}
errno = serrno;
debug_return_int(-1);
}
}
if (lseek(fd, 0, SEEK_SET) == -1) {
sudo_warn("lseek");
debug_return_int(-1);
}
debug_return_int(0);
}
/*
* Copy the temporary files specified in tf to the originals.
* Returns the number of copy errors or 0 if completely successful.
@@ -703,9 +644,7 @@ static int
sudo_edit_copy_tfiles(struct command_details *command_details,
struct tempfile *tf, int nfiles, struct timespec *times)
{
int i, tfd, ofd, rc, errors = 0;
char buf[BUFSIZ];
ssize_t nwritten, nread;
int i, tfd, ofd, errors = 0;
struct timespec ts;
struct stat sb;
mode_t oldmask;
@@ -713,7 +652,7 @@ sudo_edit_copy_tfiles(struct command_details *command_details,
/* Copy contents of temp files to real ones. */
for (i = 0; i < nfiles; i++) {
rc = -1;
int rc = -1;
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"seteuid(%u)", (unsigned int)user_details.uid);
if (seteuid(user_details.uid) != 0)
@@ -726,8 +665,8 @@ sudo_edit_copy_tfiles(struct command_details *command_details,
"seteuid(%u)", ROOT_UID);
if (seteuid(ROOT_UID) != 0)
sudo_fatal("seteuid(ROOT_UID)");
if (rc || !S_ISREG(sb.st_mode)) {
if (rc)
if (rc == -1 || !S_ISREG(sb.st_mode)) {
if (rc == -1)
sudo_warn("%s", tf[i].tfile);
else
sudo_warnx(U_("%s: not a regular file"), tf[i].tfile);
@@ -758,46 +697,19 @@ sudo_edit_copy_tfiles(struct command_details *command_details,
umask(oldmask);
switch_user(ROOT_UID, user_details.egid,
user_details.ngroups, user_details.groups);
if (ofd == -1)
goto write_error;
/* Extend the file to the new size if larger before copying. */
if (tf[i].osize > 0 && sb.st_size > tf[i].osize) {
if (sudo_edit_extend_file(ofd, sb.st_size) == -1)
goto write_error;
}
/* Overwrite the old file with the new contents. */
while ((nread = read(tfd, buf, sizeof(buf))) > 0) {
ssize_t off = 0;
do {
nwritten = write(ofd, buf + off, nread - off);
if (nwritten == -1)
goto write_error;
off += nwritten;
} while (nread > off);
}
if (nread == 0) {
/* success, read to EOF */
if (tf[i].osize > 0 && sb.st_size < tf[i].osize) {
/* We don't open with O_TRUNC so must truncate manually. */
if (ftruncate(ofd, sb.st_size) == -1) {
sudo_debug_printf(
SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
"unable to truncate %s to %lld", tf[i].ofile,
(long long)sb.st_size);
goto write_error;
}
}
unlink(tf[i].tfile);
} else if (nread < 0) {
sudo_warn(U_("unable to read temporary file"));
sudo_warnx(U_("contents of edit session left in %s"), tf[i].tfile);
errors++;
} else {
write_error:
if (ofd == -1) {
sudo_warn(U_("unable to write to %s"), tf[i].ofile);
goto bad;
}
/* Overwrite the old file with the new contents. */
if (sudo_copy_file(tf[i].tfile, tfd, sb.st_size, tf[i].ofile, ofd,
tf[i].osize) == -1) {
bad:
sudo_warnx(U_("contents of edit session left in %s"), tf[i].tfile);
errors++;
}
if (ofd != -1)
close(ofd);
close(tfd);

3
src/sudo_exec.h
View File

@@ -84,6 +84,9 @@
struct command_details;
struct command_status;
/* copy_file.c */
int sudo_copy_file(const char *src, int src_fd, off_t src_len, const char *dst, int dst_fd, off_t dst_len);
/* exec.c */
void exec_cmnd(struct command_details *details, int errfd);
void terminate_command(pid_t pid, bool use_pgrp);