From ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879 Mon Sep 17 00:00:00 2001 From: Peter Jones Date: Mon, 8 Feb 2016 14:48:15 -0500 Subject: efi: Make efivarfs entries immutable by default "rm -rf" is bricking some peoples' laptops because of variables being used to store non-reinitializable firmware driver data that's required to POST the hardware. These are 100% bugs, and they need to be fixed, but in the mean time it shouldn't be easy to *accidentally* brick machines. We have to have delete working, and picking which variables do and don't work for deletion is quite intractable, so instead make everything immutable by default (except for a whitelist), and make tools that aren't quite so broad-spectrum unset the immutable flag. Signed-off-by: Peter Jones Tested-by: Lee, Chun-Yi Acked-by: Matthew Garrett Signed-off-by: Matt Fleming --- tools/testing/selftests/efivarfs/efivarfs.sh | 19 +++++-- tools/testing/selftests/efivarfs/open-unlink.c | 72 +++++++++++++++++++++++++- 2 files changed, 87 insertions(+), 4 deletions(-) (limited to 'tools/testing/selftests/efivarfs') diff --git a/tools/testing/selftests/efivarfs/efivarfs.sh b/tools/testing/selftests/efivarfs/efivarfs.sh index 77edcdcc016b..057278448515 100755 --- a/tools/testing/selftests/efivarfs/efivarfs.sh +++ b/tools/testing/selftests/efivarfs/efivarfs.sh @@ -88,7 +88,11 @@ test_delete() exit 1 fi - rm $file + rm $file 2>/dev/null + if [ $? -ne 0 ]; then + chattr -i $file + rm $file + fi if [ -e $file ]; then echo "$file couldn't be deleted" >&2 @@ -111,6 +115,7 @@ test_zero_size_delete() exit 1 fi + chattr -i $file printf "$attrs" > $file if [ -e $file ]; then @@ -141,7 +146,11 @@ test_valid_filenames() echo "$file could not be created" >&2 ret=1 else - rm $file + rm $file 2>/dev/null + if [ $? -ne 0 ]; then + chattr -i $file + rm $file + fi fi done @@ -174,7 +183,11 @@ test_invalid_filenames() if [ -e $file ]; then echo "Creating $file should have failed" >&2 - rm $file + rm $file 2>/dev/null + if [ $? -ne 0 ]; then + chattr -i $file + rm $file + fi ret=1 fi done diff --git a/tools/testing/selftests/efivarfs/open-unlink.c b/tools/testing/selftests/efivarfs/open-unlink.c index 8c0764407b3c..4af74f733036 100644 --- a/tools/testing/selftests/efivarfs/open-unlink.c +++ b/tools/testing/selftests/efivarfs/open-unlink.c @@ -1,10 +1,68 @@ +#include #include #include #include #include +#include #include #include #include +#include + +static int set_immutable(const char *path, int immutable) +{ + unsigned int flags; + int fd; + int rc; + int error; + + fd = open(path, O_RDONLY); + if (fd < 0) + return fd; + + rc = ioctl(fd, FS_IOC_GETFLAGS, &flags); + if (rc < 0) { + error = errno; + close(fd); + errno = error; + return rc; + } + + if (immutable) + flags |= FS_IMMUTABLE_FL; + else + flags &= ~FS_IMMUTABLE_FL; + + rc = ioctl(fd, FS_IOC_SETFLAGS, &flags); + error = errno; + close(fd); + errno = error; + return rc; +} + +static int get_immutable(const char *path) +{ + unsigned int flags; + int fd; + int rc; + int error; + + fd = open(path, O_RDONLY); + if (fd < 0) + return fd; + + rc = ioctl(fd, FS_IOC_GETFLAGS, &flags); + if (rc < 0) { + error = errno; + close(fd); + errno = error; + return rc; + } + close(fd); + if (flags & FS_IMMUTABLE_FL) + return 1; + return 0; +} int main(int argc, char **argv) { @@ -27,7 +85,7 @@ int main(int argc, char **argv) buf[4] = 0; /* create a test variable */ - fd = open(path, O_WRONLY | O_CREAT); + fd = open(path, O_WRONLY | O_CREAT, 0600); if (fd < 0) { perror("open(O_WRONLY)"); return EXIT_FAILURE; @@ -41,6 +99,18 @@ int main(int argc, char **argv) close(fd); + rc = get_immutable(path); + if (rc < 0) { + perror("ioctl(FS_IOC_GETFLAGS)"); + return EXIT_FAILURE; + } else if (rc) { + rc = set_immutable(path, 0); + if (rc < 0) { + perror("ioctl(FS_IOC_SETFLAGS)"); + return EXIT_FAILURE; + } + } + fd = open(path, O_RDONLY); if (fd < 0) { perror("open"); -- cgit v1.2.3-59-g8ed1b