| Message ID | 20210121173003.18324-2-nramas@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] ima: Free IMA measurement buffer on error | expand |
On 2021-01-21 09:30:03, Lakshmi Ramasubramanian wrote: > IMA allocates kernel virtual memory to carry forward the measurement > list, from the current kernel to the next kernel on kexec system call, > in ima_add_kexec_buffer() function. This buffer is not freed before > completing the kexec system call resulting in memory leak. > > Add ima_buffer field in "struct kimage" to store the virtual address > of the buffer allocated for the IMA measurement list. > Free the memory allocated for the IMA measurement list in > kimage_file_post_load_cleanup() function. > > Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> > Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com> > Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list") Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Tyler > --- > include/linux/kexec.h | 5 +++++ > kernel/kexec_file.c | 5 +++++ > security/integrity/ima/ima_kexec.c | 2 ++ > 3 files changed, 12 insertions(+) > > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index 9e93bef52968..5f61389f5f36 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -300,6 +300,11 @@ struct kimage { > /* Information for loading purgatory */ > struct purgatory_info purgatory_info; > #endif > + > +#ifdef CONFIG_IMA_KEXEC > + /* Virtual address of IMA measurement buffer for kexec syscall */ > + void *ima_buffer; > +#endif > }; > > /* kexec interface functions */ > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index b02086d70492..5c3447cf7ad5 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -166,6 +166,11 @@ void kimage_file_post_load_cleanup(struct kimage *image) > vfree(pi->sechdrs); > pi->sechdrs = NULL; > > +#ifdef CONFIG_IMA_KEXEC > + vfree(image->ima_buffer); > + image->ima_buffer = NULL; > +#endif /* CONFIG_IMA_KEXEC */ > + > /* See if architecture has anything to cleanup post load */ > arch_kimage_file_post_load_cleanup(image); > > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index 212145008a01..8eadd0674629 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -130,6 +130,8 @@ void ima_add_kexec_buffer(struct kimage *image) > return; > } > > + image->ima_buffer = kexec_buffer; > + > pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", > kbuf.mem); > } > -- > 2.30.0 >
Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes: > IMA allocates kernel virtual memory to carry forward the measurement > list, from the current kernel to the next kernel on kexec system call, > in ima_add_kexec_buffer() function. This buffer is not freed before > completing the kexec system call resulting in memory leak. > > Add ima_buffer field in "struct kimage" to store the virtual address > of the buffer allocated for the IMA measurement list. > Free the memory allocated for the IMA measurement list in > kimage_file_post_load_cleanup() function. > > Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> > Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com> > Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list") Good catch. Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
On 1/22/21 2:31 PM, Thiago Jung Bauermann wrote: > > Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes: > >> IMA allocates kernel virtual memory to carry forward the measurement >> list, from the current kernel to the next kernel on kexec system call, >> in ima_add_kexec_buffer() function. This buffer is not freed before >> completing the kexec system call resulting in memory leak. >> >> Add ima_buffer field in "struct kimage" to store the virtual address >> of the buffer allocated for the IMA measurement list. >> Free the memory allocated for the IMA measurement list in >> kimage_file_post_load_cleanup() function. >> >> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> >> Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com> >> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list") > > Good catch. > > Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> > Thanks Thiago. -lakshmi
diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 9e93bef52968..5f61389f5f36 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -300,6 +300,11 @@ struct kimage { /* Information for loading purgatory */ struct purgatory_info purgatory_info; #endif + +#ifdef CONFIG_IMA_KEXEC + /* Virtual address of IMA measurement buffer for kexec syscall */ + void *ima_buffer; +#endif }; /* kexec interface functions */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index b02086d70492..5c3447cf7ad5 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -166,6 +166,11 @@ void kimage_file_post_load_cleanup(struct kimage *image) vfree(pi->sechdrs); pi->sechdrs = NULL; +#ifdef CONFIG_IMA_KEXEC + vfree(image->ima_buffer); + image->ima_buffer = NULL; +#endif /* CONFIG_IMA_KEXEC */ + /* See if architecture has anything to cleanup post load */ arch_kimage_file_post_load_cleanup(image); diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 212145008a01..8eadd0674629 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -130,6 +130,8 @@ void ima_add_kexec_buffer(struct kimage *image) return; } + image->ima_buffer = kexec_buffer; + pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", kbuf.mem); }
IMA allocates kernel virtual memory to carry forward the measurement list, from the current kernel to the next kernel on kexec system call, in ima_add_kexec_buffer() function. This buffer is not freed before completing the kexec system call resulting in memory leak. Add ima_buffer field in "struct kimage" to store the virtual address of the buffer allocated for the IMA measurement list. Free the memory allocated for the IMA measurement list in kimage_file_post_load_cleanup() function. Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list") --- include/linux/kexec.h | 5 +++++ kernel/kexec_file.c | 5 +++++ security/integrity/ima/ima_kexec.c | 2 ++ 3 files changed, 12 insertions(+)