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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-15 08:08:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-15 08:08:51 -0700 |
commit | 0cdd776ec92c0fec768c7079331804d3e52d4b27 (patch) | |
tree | ad2a71928a96dba897ad786e2881682dcc503279 /drivers | |
parent | 5becde60ed4e63858385aa10354cb87d7444b9cf (diff) | |
parent | 575f00edea0a7117e6a4337800ebf62e2a1d09d6 (diff) | |
download | linux-0cdd776ec92c0fec768c7079331804d3e52d4b27.tar.bz2 |
Merge tag 'driver-core-5.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH:
"Here is one fix, and three documentation updates for 5.18-rc7.
The fix is for the firmware loader which resolves a long-reported
problem where the credentials of the firmware loader could be set to a
userspace process without enough permissions to actually load the
firmware image. Many Android vendors have been reporting this for
quite some time.
The documentation updates are for the embargoed-hardware-issues.rst
file to add a new entry, change an existing one, and sort the list to
make changes easier in the future.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-5.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
Documentation/process: Update ARM contact for embargoed hardware issues
Documentation/process: Add embargoed HW contact for Ampere Computing
Documentation/process: Make groups alphabetical and use tabs consistently
firmware_loader: use kernel credentials when reading firmware
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/base/firmware_loader/main.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index 94d1789a233e..406a907a4cae 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -735,6 +735,8 @@ _request_firmware(const struct firmware **firmware_p, const char *name, size_t offset, u32 opt_flags) { struct firmware *fw = NULL; + struct cred *kern_cred = NULL; + const struct cred *old_cred; bool nondirect = false; int ret; @@ -751,6 +753,18 @@ _request_firmware(const struct firmware **firmware_p, const char *name, if (ret <= 0) /* error or already assigned */ goto out; + /* + * We are about to try to access the firmware file. Because we may have been + * called by a driver when serving an unrelated request from userland, we use + * the kernel credentials to read the file. + */ + kern_cred = prepare_kernel_cred(NULL); + if (!kern_cred) { + ret = -ENOMEM; + goto out; + } + old_cred = override_creds(kern_cred); + ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL); /* Only full reads can support decompression, platform, and sysfs. */ @@ -776,6 +790,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name, } else ret = assign_fw(fw, device); + revert_creds(old_cred); + put_cred(kern_cred); + out: if (ret < 0) { fw_abort_batch_reqs(fw); |