| Message ID | 20240214153827.1087657-6-tusharsu@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima: kexec: measure events between kexec load and execute | expand |
On 2/14/24 10:38, Tushar Sugandhi wrote: > ima_dump_measurement_list() is called during kexec 'load', which may > result in loss of IMA measurements during kexec soft reboot. It needs > to be called during kexec 'execute'. > > This patch includes the following changes: > - Call kimage_file_post_load() from kexec_file_load() syscall only for > kexec soft reboot scenarios and not for KEXEC_FILE_ON_CRASH. It will > map the IMA segment, and register reboot notifier for the function > ima_update_kexec_buffer() which would copy the IMA log at kexec soft > reboot. > - Make kexec_segment_size variable local static to the file, for it to be > accessible both during kexec 'load' and 'execute'. > - Move ima_dump_measurement_list() call from ima_add_kexec_buffer() > to ima_update_kexec_buffer(). > - Remove ima_reset_kexec_file() call from ima_add_kexec_buffer(), now > that the buffer is being copied at kexec 'execute', and resetting the > file at kexec 'load' will corrupt the buffer. > > Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> > --- > kernel/kexec_file.c | 3 ++ > security/integrity/ima/ima_kexec.c | 45 +++++++++++++++++++----------- > 2 files changed, 32 insertions(+), 16 deletions(-) > > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index fe59cb7c179d..2d5df320c34f 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -410,6 +410,9 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, > > kimage_terminate(image); > > + if (!(flags & KEXEC_FILE_ON_CRASH)) > + kimage_file_post_load(image); > + > ret = machine_kexec_post_load(image); > if (ret) > goto out; > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index 1d4d6c122d82..98fc9b9782a2 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -19,6 +19,7 @@ > #ifdef CONFIG_IMA_KEXEC > static struct seq_file ima_kexec_file; > static void *ima_kexec_buffer; > +static size_t kexec_segment_size; > static bool ima_kexec_update_registered; > > static void ima_reset_kexec_file(struct seq_file *sf) > @@ -129,7 +130,6 @@ void ima_add_kexec_buffer(struct kimage *image) > /* use more understandable variable names than defined in kbuf */ > void *kexec_buffer = NULL; > size_t kexec_buffer_size; > - size_t kexec_segment_size; > int ret; > > /* > @@ -154,14 +154,6 @@ void ima_add_kexec_buffer(struct kimage *image) > return; > } > > - ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, > - kexec_segment_size); > - if (ret < 0) { > - pr_err("%s: Failed to dump IMA measurements. Error:%d.\n", > - __func__, ret); > - return; > - } > - > kbuf.buffer = kexec_buffer; > kbuf.bufsz = kexec_buffer_size; > kbuf.memsz = kexec_segment_size; > @@ -179,12 +171,6 @@ void ima_add_kexec_buffer(struct kimage *image) > image->ima_segment_index = image->nr_segments - 1; > image->is_ima_segment_index_set = true; > > - /* > - * kexec owns kexec_buffer after kexec_add_buffer() is called > - * and it will vfree() that buffer. > - */ > - ima_reset_kexec_file(&ima_kexec_file); > - > kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n", > kbuf.mem); > } > @@ -195,7 +181,34 @@ void ima_add_kexec_buffer(struct kimage *image) > static int ima_update_kexec_buffer(struct notifier_block *self, > unsigned long action, void *data) > { > - return NOTIFY_OK; > + void *buf = NULL; > + size_t buf_size; > + int ret = NOTIFY_OK; > + > + if (!kexec_in_progress) { > + pr_info("%s: No kexec in progress.\n", __func__); > + return ret; > + } > + > + if (!ima_kexec_buffer) { > + pr_err("%s: Kexec buffer not set.\n", __func__); > + return ret; > + } > + > + ret = ima_dump_measurement_list(&buf_size, &buf, > + kexec_segment_size); > + > + if (!buf) { Use 'if (ret)' ? You're setting *buffer = NULL in case of error but ret should be used to test for failure. > + pr_err("%s: Dump measurements failed. Error:%d\n", > + __func__, ret); > + goto out; > + } > + memcpy(ima_kexec_buffer, buf, buf_size); > +out: > + kimage_unmap_segment(ima_kexec_buffer); > + ima_kexec_buffer = NULL; > + > + return ret; > } > > struct notifier_block update_buffer_nb = {
> @@ -195,7 +181,34 @@ void ima_add_kexec_buffer(struct kimage *image) > static int ima_update_kexec_buffer(struct notifier_block *self, > unsigned long action, void *data) > { > - return NOTIFY_OK; > + void *buf = NULL; > + size_t buf_size; > + int ret = NOTIFY_OK; > + > + if (!kexec_in_progress) { > + pr_info("%s: No kexec in progress.\n", __func__); > + return ret; > + } > + > + if (!ima_kexec_buffer) { > + pr_err("%s: Kexec buffer not set.\n", __func__); > + return ret; > + } pr_ messages should already be prefixed with the module name. There shouldn't be a need to include the function name as well. > + ret = ima_dump_measurement_list(&buf_size, &buf, > + kexec_segment_size); > + > + if (!buf) { > + pr_err("%s: Dump measurements failed. Error:%d\n", > + __func__, ret); > + goto out; > + } > + memcpy(ima_kexec_buffer, buf, buf_size); > +out: > + kimage_unmap_segment(ima_kexec_buffer); > + ima_kexec_buffer = NULL; > + > + return ret; > } > > struct notifier_block update_buffer_nb = {
On Wed, 14 Feb 2024 07:38:24 -0800 Tushar Sugandhi <tusharsu@linux.microsoft.com> wrote: > ima_dump_measurement_list() is called during kexec 'load', which may > result in loss of IMA measurements during kexec soft reboot. It needs > to be called during kexec 'execute'. > > This patch includes the following changes: > - Call kimage_file_post_load() from kexec_file_load() syscall only for > kexec soft reboot scenarios and not for KEXEC_FILE_ON_CRASH. It will > map the IMA segment, and register reboot notifier for the function > ima_update_kexec_buffer() which would copy the IMA log at kexec soft > reboot. > - Make kexec_segment_size variable local static to the file, for it to be > accessible both during kexec 'load' and 'execute'. > - Move ima_dump_measurement_list() call from ima_add_kexec_buffer() > to ima_update_kexec_buffer(). > - Remove ima_reset_kexec_file() call from ima_add_kexec_buffer(), now > that the buffer is being copied at kexec 'execute', and resetting the > file at kexec 'load' will corrupt the buffer. > > Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> > --- > kernel/kexec_file.c | 3 ++ > security/integrity/ima/ima_kexec.c | 45 +++++++++++++++++++----------- > 2 files changed, 32 insertions(+), 16 deletions(-) > > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index fe59cb7c179d..2d5df320c34f 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -410,6 +410,9 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, > > kimage_terminate(image); > > + if (!(flags & KEXEC_FILE_ON_CRASH)) > + kimage_file_post_load(image); > + > ret = machine_kexec_post_load(image); > if (ret) > goto out; > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index 1d4d6c122d82..98fc9b9782a2 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -19,6 +19,7 @@ > #ifdef CONFIG_IMA_KEXEC > static struct seq_file ima_kexec_file; > static void *ima_kexec_buffer; > +static size_t kexec_segment_size; > static bool ima_kexec_update_registered; > > static void ima_reset_kexec_file(struct seq_file *sf) > @@ -129,7 +130,6 @@ void ima_add_kexec_buffer(struct kimage *image) > /* use more understandable variable names than defined in kbuf */ > void *kexec_buffer = NULL; > size_t kexec_buffer_size; > - size_t kexec_segment_size; > int ret; > > /* > @@ -154,14 +154,6 @@ void ima_add_kexec_buffer(struct kimage *image) > return; > } > > - ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, > - kexec_segment_size); > - if (ret < 0) { > - pr_err("%s: Failed to dump IMA measurements. Error:%d.\n", > - __func__, ret); > - return; > - } > - After removing these lines... > kbuf.buffer = kexec_buffer; > kbuf.bufsz = kexec_buffer_size; ^^^^^^^^^^^^^^^^^ ... kexec_buffer_size is uninitialized here. Petr T
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index fe59cb7c179d..2d5df320c34f 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -410,6 +410,9 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, kimage_terminate(image); + if (!(flags & KEXEC_FILE_ON_CRASH)) + kimage_file_post_load(image); + ret = machine_kexec_post_load(image); if (ret) goto out; diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 1d4d6c122d82..98fc9b9782a2 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -19,6 +19,7 @@ #ifdef CONFIG_IMA_KEXEC static struct seq_file ima_kexec_file; static void *ima_kexec_buffer; +static size_t kexec_segment_size; static bool ima_kexec_update_registered; static void ima_reset_kexec_file(struct seq_file *sf) @@ -129,7 +130,6 @@ void ima_add_kexec_buffer(struct kimage *image) /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; size_t kexec_buffer_size; - size_t kexec_segment_size; int ret; /* @@ -154,14 +154,6 @@ void ima_add_kexec_buffer(struct kimage *image) return; } - ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, - kexec_segment_size); - if (ret < 0) { - pr_err("%s: Failed to dump IMA measurements. Error:%d.\n", - __func__, ret); - return; - } - kbuf.buffer = kexec_buffer; kbuf.bufsz = kexec_buffer_size; kbuf.memsz = kexec_segment_size; @@ -179,12 +171,6 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_segment_index = image->nr_segments - 1; image->is_ima_segment_index_set = true; - /* - * kexec owns kexec_buffer after kexec_add_buffer() is called - * and it will vfree() that buffer. - */ - ima_reset_kexec_file(&ima_kexec_file); - kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n", kbuf.mem); } @@ -195,7 +181,34 @@ void ima_add_kexec_buffer(struct kimage *image) static int ima_update_kexec_buffer(struct notifier_block *self, unsigned long action, void *data) { - return NOTIFY_OK; + void *buf = NULL; + size_t buf_size; + int ret = NOTIFY_OK; + + if (!kexec_in_progress) { + pr_info("%s: No kexec in progress.\n", __func__); + return ret; + } + + if (!ima_kexec_buffer) { + pr_err("%s: Kexec buffer not set.\n", __func__); + return ret; + } + + ret = ima_dump_measurement_list(&buf_size, &buf, + kexec_segment_size); + + if (!buf) { + pr_err("%s: Dump measurements failed. Error:%d\n", + __func__, ret); + goto out; + } + memcpy(ima_kexec_buffer, buf, buf_size); +out: + kimage_unmap_segment(ima_kexec_buffer); + ima_kexec_buffer = NULL; + + return ret; } struct notifier_block update_buffer_nb = {
ima_dump_measurement_list() is called during kexec 'load', which may result in loss of IMA measurements during kexec soft reboot. It needs to be called during kexec 'execute'. This patch includes the following changes: - Call kimage_file_post_load() from kexec_file_load() syscall only for kexec soft reboot scenarios and not for KEXEC_FILE_ON_CRASH. It will map the IMA segment, and register reboot notifier for the function ima_update_kexec_buffer() which would copy the IMA log at kexec soft reboot. - Make kexec_segment_size variable local static to the file, for it to be accessible both during kexec 'load' and 'execute'. - Move ima_dump_measurement_list() call from ima_add_kexec_buffer() to ima_update_kexec_buffer(). - Remove ima_reset_kexec_file() call from ima_add_kexec_buffer(), now that the buffer is being copied at kexec 'execute', and resetting the file at kexec 'load' will corrupt the buffer. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> --- kernel/kexec_file.c | 3 ++ security/integrity/ima/ima_kexec.c | 45 +++++++++++++++++++----------- 2 files changed, 32 insertions(+), 16 deletions(-)