| Message ID | 20230908104458.775740-1-songshuaishuai@tinylab.org |
|---|---|
| State | Rejected |
| Headers | show |
| Series | of/kexec: Omit kaslr-seed when kexecing with nokaslr | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | warning | total: 0 errors, 1 warnings, 39 lines checked |
| robh/patch-applied | fail | build log |
On Fri, Sep 8, 2023 at 5:45 AM Song Shuai <songshuaishuai@tinylab.org> wrote: > > The chosen node always adds the kaslr-seed property which is needless > for the kernels kexeced with the cmdline contained "nokaslr". > > So omit the kaslr-seed when kexecing with nokaslr. The kexec'ed kernel can ignore bootargs with CONFIG_CMDLINE_FORCE. So you don't know if kaslr-seed will be used or not. > Signed-off-by: Song Shuai <songshuaishuai@tinylab.org> > --- > drivers/of/kexec.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c > index f26d2ba8a371..c0d53b10cb70 100644 > --- a/drivers/of/kexec.c > +++ b/drivers/of/kexec.c > @@ -19,6 +19,7 @@ > #include <linux/random.h> > #include <linux/slab.h> > #include <linux/types.h> > +#include <linux/string.h> > > #define RNG_SEED_SIZE 128 > > @@ -263,6 +264,14 @@ static inline int setup_ima_buffer(const struct kimage *image, void *fdt, > } > #endif /* CONFIG_IMA_KEXEC */ > > +static bool is_nokaslr_cmdline(const char *cmdline) > +{ > + char *str; > + > + str = strstr(cmdline, "nokaslr"); > + return str == cmdline || (str > cmdline && *(str - 1) == ' '); Yet another copy of the same code. That's a clue to refactor into a common function. Rob
在 2023/9/8 22:58, Rob Herring 写道: > On Fri, Sep 8, 2023 at 5:45 AM Song Shuai <songshuaishuai@tinylab.org> wrote: >> >> The chosen node always adds the kaslr-seed property which is needless >> for the kernels kexeced with the cmdline contained "nokaslr". >> >> So omit the kaslr-seed when kexecing with nokaslr. > > The kexec'ed kernel can ignore bootargs with CONFIG_CMDLINE_FORCE. So > you don't know if kaslr-seed will be used or not. > You are correct. In addition, unlike the EFI Stub, Kexec is unable to determine whether the kexec'ed kernel supports RANDOMIZE_BASE, hence it is appropriate to emit the kaslr-seed unconditionally like those out-of-linux bootloaders. Apologies for bothering you with this incorrect patch. >> Signed-off-by: Song Shuai <songshuaishuai@tinylab.org> >> --- >> drivers/of/kexec.c | 15 ++++++++++++--- >> 1 file changed, 12 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c >> index f26d2ba8a371..c0d53b10cb70 100644 >> --- a/drivers/of/kexec.c >> +++ b/drivers/of/kexec.c >> @@ -19,6 +19,7 @@ >> #include <linux/random.h> >> #include <linux/slab.h> >> #include <linux/types.h> >> +#include <linux/string.h> >> >> #define RNG_SEED_SIZE 128 >> >> @@ -263,6 +264,14 @@ static inline int setup_ima_buffer(const struct kimage *image, void *fdt, >> } >> #endif /* CONFIG_IMA_KEXEC */ >> >> +static bool is_nokaslr_cmdline(const char *cmdline) >> +{ >> + char *str; >> + >> + str = strstr(cmdline, "nokaslr"); >> + return str == cmdline || (str > cmdline && *(str - 1) == ' '); > > Yet another copy of the same code. That's a clue to refactor into a > common function. > > Rob >
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c index f26d2ba8a371..c0d53b10cb70 100644 --- a/drivers/of/kexec.c +++ b/drivers/of/kexec.c @@ -19,6 +19,7 @@ #include <linux/random.h> #include <linux/slab.h> #include <linux/types.h> +#include <linux/string.h> #define RNG_SEED_SIZE 128 @@ -263,6 +264,14 @@ static inline int setup_ima_buffer(const struct kimage *image, void *fdt, } #endif /* CONFIG_IMA_KEXEC */ +static bool is_nokaslr_cmdline(const char *cmdline) +{ + char *str; + + str = strstr(cmdline, "nokaslr"); + return str == cmdline || (str > cmdline && *(str - 1) == ' '); +} + /* * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree * @@ -429,15 +438,15 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, else if (ret) goto out; - if (rng_is_initialized()) { + if (!is_nokaslr_cmdline(cmdline) && rng_is_initialized()) { u64 seed = get_random_u64(); ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed); if (ret) goto out; } else { - pr_notice("RNG is not initialised: omitting \"%s\" property\n", - "kaslr-seed"); + pr_notice("RNG is not initialised or Kexec with nokaslr:" + " omitting \"%s\" property\n", "kaslr-seed"); } /* add rng-seed */
The chosen node always adds the kaslr-seed property which is needless for the kernels kexeced with the cmdline contained "nokaslr". So omit the kaslr-seed when kexecing with nokaslr. Signed-off-by: Song Shuai <songshuaishuai@tinylab.org> --- drivers/of/kexec.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)