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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /samples/check-exec | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'samples/check-exec')
| -rw-r--r-- | samples/check-exec/.gitignore | 2 | ||||
| -rw-r--r-- | samples/check-exec/Makefile | 15 | ||||
| -rw-r--r-- | samples/check-exec/inc.c | 212 | ||||
| -rwxr-xr-x | samples/check-exec/run-script-ask.sh | 9 | ||||
| -rwxr-xr-x | samples/check-exec/script-ask.inc | 5 | ||||
| -rwxr-xr-x | samples/check-exec/script-exec.inc | 4 | ||||
| -rw-r--r-- | samples/check-exec/script-noexec.inc | 4 | ||||
| -rw-r--r-- | samples/check-exec/set-exec.c | 85 |
8 files changed, 336 insertions, 0 deletions
diff --git a/samples/check-exec/.gitignore b/samples/check-exec/.gitignore new file mode 100644 index 000000000..cd759a19d --- /dev/null +++ b/samples/check-exec/.gitignore @@ -0,0 +1,2 @@ +/inc +/set-exec diff --git a/samples/check-exec/Makefile b/samples/check-exec/Makefile new file mode 100644 index 000000000..c4f08ad0f --- /dev/null +++ b/samples/check-exec/Makefile @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: BSD-3-Clause + +userprogs-always-y := \ + inc \ + set-exec + +userccflags += -I usr/include + +.PHONY: all clean + +all: + $(MAKE) -C ../.. samples/check-exec/ + +clean: + $(MAKE) -C ../.. M=samples/check-exec/ clean diff --git a/samples/check-exec/inc.c b/samples/check-exec/inc.c new file mode 100644 index 000000000..7f6ef06a2 --- /dev/null +++ b/samples/check-exec/inc.c @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* + * Very simple script interpreter that can evaluate two different commands (one + * per line): + * - "?" to initialize a counter from user's input; + * - "+" to increment the counter (which is set to 0 by default). + * + * See tools/testing/selftests/exec/check-exec-tests.sh and + * Documentation/userspace-api/check_exec.rst + * + * Copyright © 2024 Microsoft Corporation + */ + +#define _GNU_SOURCE +#include <errno.h> +#include <linux/fcntl.h> +#include <linux/prctl.h> +#include <linux/securebits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/prctl.h> +#include <sys/syscall.h> +#include <unistd.h> + +static int sys_execveat(int dirfd, const char *pathname, char *const argv[], + char *const envp[], int flags) +{ + return syscall(__NR_execveat, dirfd, pathname, argv, envp, flags); +} + +/* Returns 1 on error, 0 otherwise. */ +static int interpret_buffer(char *buffer, size_t buffer_size) +{ + char *line, *saveptr = NULL; + long long number = 0; + + /* Each command is the first character of a line. */ + saveptr = NULL; + line = strtok_r(buffer, "\n", &saveptr); + while (line) { + if (*line != '#' && strlen(line) != 1) { + fprintf(stderr, "# ERROR: Unknown string\n"); + return 1; + } + switch (*line) { + case '#': + /* Skips shebang and comments. */ + break; + case '+': + /* Increments and prints the number. */ + number++; + printf("%lld\n", number); + break; + case '?': + /* Reads integer from stdin. */ + fprintf(stderr, "> Enter new number: \n"); + if (scanf("%lld", &number) != 1) { + fprintf(stderr, + "# WARNING: Failed to read number from stdin\n"); + } + break; + default: + fprintf(stderr, "# ERROR: Unknown character '%c'\n", + *line); + return 1; + } + line = strtok_r(NULL, "\n", &saveptr); + } + return 0; +} + +/* Returns 1 on error, 0 otherwise. */ +static int interpret_stream(FILE *script, char *const script_name, + char *const *const envp, const bool restrict_stream) +{ + int err; + char *const script_argv[] = { script_name, NULL }; + char buf[128] = {}; + size_t buf_size = sizeof(buf); + + /* + * We pass a valid argv and envp to the kernel to emulate a native + * script execution. We must use the script file descriptor instead of + * the script path name to avoid race conditions. + */ + err = sys_execveat(fileno(script), "", script_argv, envp, + AT_EMPTY_PATH | AT_EXECVE_CHECK); + if (err && restrict_stream) { + perror("ERROR: Script execution check"); + return 1; + } + + /* Reads script. */ + buf_size = fread(buf, 1, buf_size - 1, script); + return interpret_buffer(buf, buf_size); +} + +static void print_usage(const char *argv0) +{ + fprintf(stderr, "usage: %s <script.inc> | -i | -c <command>\n\n", + argv0); + fprintf(stderr, "Example:\n"); + fprintf(stderr, " ./set-exec -fi -- ./inc -i < script-exec.inc\n"); +} + +int main(const int argc, char *const argv[], char *const *const envp) +{ + int opt; + char *cmd = NULL; + char *script_name = NULL; + bool interpret_stdin = false; + FILE *script_file = NULL; + int secbits; + bool deny_interactive, restrict_file; + size_t arg_nb; + + secbits = prctl(PR_GET_SECUREBITS); + if (secbits == -1) { + /* + * This should never happen, except with a buggy seccomp + * filter. + */ + perror("ERROR: Failed to get securebits"); + return 1; + } + + deny_interactive = !!(secbits & SECBIT_EXEC_DENY_INTERACTIVE); + restrict_file = !!(secbits & SECBIT_EXEC_RESTRICT_FILE); + + while ((opt = getopt(argc, argv, "c:i")) != -1) { + switch (opt) { + case 'c': + if (cmd) { + fprintf(stderr, "ERROR: Command already set"); + return 1; + } + cmd = optarg; + break; + case 'i': + interpret_stdin = true; + break; + default: + print_usage(argv[0]); + return 1; + } + } + + /* Checks that only one argument is used, or read stdin. */ + arg_nb = !!cmd + !!interpret_stdin; + if (arg_nb == 0 && argc == 2) { + script_name = argv[1]; + } else if (arg_nb != 1) { + print_usage(argv[0]); + return 1; + } + + if (cmd) { + /* + * Other kind of interactive interpretations should be denied + * as well (e.g. CLI arguments passing script snippets, + * environment variables interpreted as script). However, any + * way to pass script files should only be restricted according + * to restrict_file. + */ + if (deny_interactive) { + fprintf(stderr, + "ERROR: Interactive interpretation denied.\n"); + return 1; + } + + return interpret_buffer(cmd, strlen(cmd)); + } + + if (interpret_stdin && !script_name) { + script_file = stdin; + /* + * As for any execve(2) call, this path may be logged by the + * kernel. + */ + script_name = "/proc/self/fd/0"; + /* + * When stdin is used, it can point to a regular file or a + * pipe. Restrict stdin execution according to + * SECBIT_EXEC_DENY_INTERACTIVE but always allow executable + * files (which are not considered as interactive inputs). + */ + return interpret_stream(script_file, script_name, envp, + deny_interactive); + } else if (script_name && !interpret_stdin) { + /* + * In this sample, we don't pass any argument to scripts, but + * otherwise we would have to forge an argv with such + * arguments. + */ + script_file = fopen(script_name, "r"); + if (!script_file) { + perror("ERROR: Failed to open script"); + return 1; + } + /* + * Restricts file execution according to + * SECBIT_EXEC_RESTRICT_FILE. + */ + return interpret_stream(script_file, script_name, envp, + restrict_file); + } + + print_usage(argv[0]); + return 1; +} diff --git a/samples/check-exec/run-script-ask.sh b/samples/check-exec/run-script-ask.sh new file mode 100755 index 000000000..8ef0fdc37 --- /dev/null +++ b/samples/check-exec/run-script-ask.sh @@ -0,0 +1,9 @@ +#!/usr/bin/env sh +# SPDX-License-Identifier: BSD-3-Clause + +DIR="$(dirname -- "$0")" + +PATH="${PATH}:${DIR}" + +set -x +"${DIR}/script-ask.inc" diff --git a/samples/check-exec/script-ask.inc b/samples/check-exec/script-ask.inc new file mode 100755 index 000000000..720a8e649 --- /dev/null +++ b/samples/check-exec/script-ask.inc @@ -0,0 +1,5 @@ +#!/usr/bin/env inc +# SPDX-License-Identifier: BSD-3-Clause + +? ++ diff --git a/samples/check-exec/script-exec.inc b/samples/check-exec/script-exec.inc new file mode 100755 index 000000000..3245cb9d8 --- /dev/null +++ b/samples/check-exec/script-exec.inc @@ -0,0 +1,4 @@ +#!/usr/bin/env inc +# SPDX-License-Identifier: BSD-3-Clause + ++ diff --git a/samples/check-exec/script-noexec.inc b/samples/check-exec/script-noexec.inc new file mode 100644 index 000000000..3245cb9d8 --- /dev/null +++ b/samples/check-exec/script-noexec.inc @@ -0,0 +1,4 @@ +#!/usr/bin/env inc +# SPDX-License-Identifier: BSD-3-Clause + ++ diff --git a/samples/check-exec/set-exec.c b/samples/check-exec/set-exec.c new file mode 100644 index 000000000..ba86a60a2 --- /dev/null +++ b/samples/check-exec/set-exec.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* + * Simple tool to set SECBIT_EXEC_RESTRICT_FILE, SECBIT_EXEC_DENY_INTERACTIVE, + * before executing a command. + * + * Copyright © 2024 Microsoft Corporation + */ + +#define _GNU_SOURCE +#define __SANE_USERSPACE_TYPES__ +#include <errno.h> +#include <linux/prctl.h> +#include <linux/securebits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/prctl.h> +#include <unistd.h> + +static void print_usage(const char *argv0) +{ + fprintf(stderr, "usage: %s -f|-i -- <cmd> [args]...\n\n", argv0); + fprintf(stderr, "Execute a command with\n"); + fprintf(stderr, "- SECBIT_EXEC_RESTRICT_FILE set: -f\n"); + fprintf(stderr, "- SECBIT_EXEC_DENY_INTERACTIVE set: -i\n"); +} + +int main(const int argc, char *const argv[], char *const *const envp) +{ + const char *cmd_path; + char *const *cmd_argv; + int opt, secbits_cur, secbits_new; + bool has_policy = false; + + secbits_cur = prctl(PR_GET_SECUREBITS); + if (secbits_cur == -1) { + /* + * This should never happen, except with a buggy seccomp + * filter. + */ + perror("ERROR: Failed to get securebits"); + return 1; + } + + secbits_new = secbits_cur; + while ((opt = getopt(argc, argv, "fi")) != -1) { + switch (opt) { + case 'f': + secbits_new |= SECBIT_EXEC_RESTRICT_FILE | + SECBIT_EXEC_RESTRICT_FILE_LOCKED; + has_policy = true; + break; + case 'i': + secbits_new |= SECBIT_EXEC_DENY_INTERACTIVE | + SECBIT_EXEC_DENY_INTERACTIVE_LOCKED; + has_policy = true; + break; + default: + print_usage(argv[0]); + return 1; + } + } + + if (!argv[optind] || !has_policy) { + print_usage(argv[0]); + return 1; + } + + if (secbits_cur != secbits_new && + prctl(PR_SET_SECUREBITS, secbits_new)) { + perror("Failed to set secure bit(s)."); + fprintf(stderr, + "Hint: The running kernel may not support this feature.\n"); + return 1; + } + + cmd_path = argv[optind]; + cmd_argv = argv + optind; + fprintf(stderr, "Executing command...\n"); + execvpe(cmd_path, cmd_argv, envp); + fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path, + strerror(errno)); + return 1; +} |
