| Message ID | d4688c2af08dda706d3b6786ae5ec5a74e6171f1.1634457599.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix LKDTM for PPC64/IA64/PARISC | expand |
Hi Kees, Le 17/10/2021 à 14:38, Christophe Leroy a écrit : > execute_location() and execute_user_location() intent > to copy do_nothing() text and execute it at a new location. > However, at the time being it doesn't copy do_nothing() function > but do_nothing() function descriptor which still points to the > original text. So at the end it still executes do_nothing() at > its original location allthough using a copied function descriptor. > > So, fix that by really copying do_nothing() text and build a new > function descriptor by copying do_nothing() function descriptor and > updating the target address with the new location. > > Also fix the displayed addresses by dereferencing do_nothing() > function descriptor. > > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Do you have any comment to this patch and to patch 12 ? If not, is it ok to get your acked-by ? Thanks Christophe > --- > drivers/misc/lkdtm/perms.c | 37 ++++++++++++++++++++++++++++--------- > 1 file changed, 28 insertions(+), 9 deletions(-) > > diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c > index 035fcca441f0..1cf24c4a79e9 100644 > --- a/drivers/misc/lkdtm/perms.c > +++ b/drivers/misc/lkdtm/perms.c > @@ -44,19 +44,34 @@ static noinline void do_overwritten(void) > return; > } > > +static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) > +{ > + if (!have_function_descriptors()) > + return dst; > + > + memcpy(fdesc, do_nothing, sizeof(*fdesc)); > + fdesc->addr = (unsigned long)dst; > + barrier(); > + > + return fdesc; > +} > + > static noinline void execute_location(void *dst, bool write) > { > - void (*func)(void) = dst; > + void (*func)(void); > + func_desc_t fdesc; > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > - pr_info("attempting ok execution at %px\n", do_nothing); > + pr_info("attempting ok execution at %px\n", do_nothing_text); > do_nothing(); > > if (write == CODE_WRITE) { > - memcpy(dst, do_nothing, EXEC_SIZE); > + memcpy(dst, do_nothing_text, EXEC_SIZE); > flush_icache_range((unsigned long)dst, > (unsigned long)dst + EXEC_SIZE); > } > - pr_info("attempting bad execution at %px\n", func); > + pr_info("attempting bad execution at %px\n", dst); > + func = setup_function_descriptor(&fdesc, dst); > func(); > pr_err("FAIL: func returned\n"); > } > @@ -66,16 +81,19 @@ static void execute_user_location(void *dst) > int copied; > > /* Intentionally crossing kernel/user memory boundary. */ > - void (*func)(void) = dst; > + void (*func)(void); > + func_desc_t fdesc; > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > - pr_info("attempting ok execution at %px\n", do_nothing); > + pr_info("attempting ok execution at %px\n", do_nothing_text); > do_nothing(); > > - copied = access_process_vm(current, (unsigned long)dst, do_nothing, > + copied = access_process_vm(current, (unsigned long)dst, do_nothing_text, > EXEC_SIZE, FOLL_WRITE); > if (copied < EXEC_SIZE) > return; > - pr_info("attempting bad execution at %px\n", func); > + pr_info("attempting bad execution at %px\n", dst); > + func = setup_function_descriptor(&fdesc, dst); > func(); > pr_err("FAIL: func returned\n"); > } > @@ -153,7 +171,8 @@ void lkdtm_EXEC_VMALLOC(void) > > void lkdtm_EXEC_RODATA(void) > { > - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); > + execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing), > + CODE_AS_IS); > } > > void lkdtm_EXEC_USERSPACE(void) >
Hi Kees, Le 17/12/2021 à 12:49, Christophe Leroy a écrit : > Hi Kees, > > Le 17/10/2021 à 14:38, Christophe Leroy a écrit : >> execute_location() and execute_user_location() intent >> to copy do_nothing() text and execute it at a new location. >> However, at the time being it doesn't copy do_nothing() function >> but do_nothing() function descriptor which still points to the >> original text. So at the end it still executes do_nothing() at >> its original location allthough using a copied function descriptor. >> >> So, fix that by really copying do_nothing() text and build a new >> function descriptor by copying do_nothing() function descriptor and >> updating the target address with the new location. >> >> Also fix the displayed addresses by dereferencing do_nothing() >> function descriptor. >> >> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > > Do you have any comment to this patch and to patch 12 ? > > If not, is it ok to get your acked-by ? Any feedback please, even if it's to say no feedback ? Many thanks, Christophe > > Thanks > Christophe > >> --- >> drivers/misc/lkdtm/perms.c | 37 ++++++++++++++++++++++++++++--------- >> 1 file changed, 28 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c >> index 035fcca441f0..1cf24c4a79e9 100644 >> --- a/drivers/misc/lkdtm/perms.c >> +++ b/drivers/misc/lkdtm/perms.c >> @@ -44,19 +44,34 @@ static noinline void do_overwritten(void) >> return; >> } >> +static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) >> +{ >> + if (!have_function_descriptors()) >> + return dst; >> + >> + memcpy(fdesc, do_nothing, sizeof(*fdesc)); >> + fdesc->addr = (unsigned long)dst; >> + barrier(); >> + >> + return fdesc; >> +} >> + >> static noinline void execute_location(void *dst, bool write) >> { >> - void (*func)(void) = dst; >> + void (*func)(void); >> + func_desc_t fdesc; >> + void *do_nothing_text = dereference_function_descriptor(do_nothing); >> - pr_info("attempting ok execution at %px\n", do_nothing); >> + pr_info("attempting ok execution at %px\n", do_nothing_text); >> do_nothing(); >> if (write == CODE_WRITE) { >> - memcpy(dst, do_nothing, EXEC_SIZE); >> + memcpy(dst, do_nothing_text, EXEC_SIZE); >> flush_icache_range((unsigned long)dst, >> (unsigned long)dst + EXEC_SIZE); >> } >> - pr_info("attempting bad execution at %px\n", func); >> + pr_info("attempting bad execution at %px\n", dst); >> + func = setup_function_descriptor(&fdesc, dst); >> func(); >> pr_err("FAIL: func returned\n"); >> } >> @@ -66,16 +81,19 @@ static void execute_user_location(void *dst) >> int copied; >> /* Intentionally crossing kernel/user memory boundary. */ >> - void (*func)(void) = dst; >> + void (*func)(void); >> + func_desc_t fdesc; >> + void *do_nothing_text = dereference_function_descriptor(do_nothing); >> - pr_info("attempting ok execution at %px\n", do_nothing); >> + pr_info("attempting ok execution at %px\n", do_nothing_text); >> do_nothing(); >> - copied = access_process_vm(current, (unsigned long)dst, do_nothing, >> + copied = access_process_vm(current, (unsigned long)dst, >> do_nothing_text, >> EXEC_SIZE, FOLL_WRITE); >> if (copied < EXEC_SIZE) >> return; >> - pr_info("attempting bad execution at %px\n", func); >> + pr_info("attempting bad execution at %px\n", dst); >> + func = setup_function_descriptor(&fdesc, dst); >> func(); >> pr_err("FAIL: func returned\n"); >> } >> @@ -153,7 +171,8 @@ void lkdtm_EXEC_VMALLOC(void) >> void lkdtm_EXEC_RODATA(void) >> { >> - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); >> + >> execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing), >> >> + CODE_AS_IS); >> } >> void lkdtm_EXEC_USERSPACE(void) >>
On Wed, Jan 19, 2022 at 08:28:54PM +0100, Christophe Leroy wrote: > Hi Kees, > > > Le 17/12/2021 à 12:49, Christophe Leroy a écrit : > > Hi Kees, > > > > Le 17/10/2021 à 14:38, Christophe Leroy a écrit : > > > execute_location() and execute_user_location() intent > > > to copy do_nothing() text and execute it at a new location. > > > However, at the time being it doesn't copy do_nothing() function > > > but do_nothing() function descriptor which still points to the > > > original text. So at the end it still executes do_nothing() at > > > its original location allthough using a copied function descriptor. > > > > > > So, fix that by really copying do_nothing() text and build a new > > > function descriptor by copying do_nothing() function descriptor and > > > updating the target address with the new location. > > > > > > Also fix the displayed addresses by dereferencing do_nothing() > > > function descriptor. > > > > > > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > > > > Do you have any comment to this patch and to patch 12 ? > > > > If not, is it ok to get your acked-by ? > > Any feedback please, even if it's to say no feedback ? Hi! Thanks for the ping; I haven't had time yet to look at this, but with -rc1 coming, I should be able to task-switch back to LKDTM for the dev cycle and I can give some feedback. -Kees > > Many thanks, > Christophe > > > > > Thanks > > Christophe > > > > > --- > > > drivers/misc/lkdtm/perms.c | 37 ++++++++++++++++++++++++++++--------- > > > 1 file changed, 28 insertions(+), 9 deletions(-) > > > > > > diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c > > > index 035fcca441f0..1cf24c4a79e9 100644 > > > --- a/drivers/misc/lkdtm/perms.c > > > +++ b/drivers/misc/lkdtm/perms.c > > > @@ -44,19 +44,34 @@ static noinline void do_overwritten(void) > > > return; > > > } > > > +static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) > > > +{ > > > + if (!have_function_descriptors()) > > > + return dst; > > > + > > > + memcpy(fdesc, do_nothing, sizeof(*fdesc)); > > > + fdesc->addr = (unsigned long)dst; > > > + barrier(); > > > + > > > + return fdesc; > > > +} > > > + > > > static noinline void execute_location(void *dst, bool write) > > > { > > > - void (*func)(void) = dst; > > > + void (*func)(void); > > > + func_desc_t fdesc; > > > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > > - pr_info("attempting ok execution at %px\n", do_nothing); > > > + pr_info("attempting ok execution at %px\n", do_nothing_text); > > > do_nothing(); > > > if (write == CODE_WRITE) { > > > - memcpy(dst, do_nothing, EXEC_SIZE); > > > + memcpy(dst, do_nothing_text, EXEC_SIZE); > > > flush_icache_range((unsigned long)dst, > > > (unsigned long)dst + EXEC_SIZE); > > > } > > > - pr_info("attempting bad execution at %px\n", func); > > > + pr_info("attempting bad execution at %px\n", dst); > > > + func = setup_function_descriptor(&fdesc, dst); > > > func(); > > > pr_err("FAIL: func returned\n"); > > > } > > > @@ -66,16 +81,19 @@ static void execute_user_location(void *dst) > > > int copied; > > > /* Intentionally crossing kernel/user memory boundary. */ > > > - void (*func)(void) = dst; > > > + void (*func)(void); > > > + func_desc_t fdesc; > > > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > > - pr_info("attempting ok execution at %px\n", do_nothing); > > > + pr_info("attempting ok execution at %px\n", do_nothing_text); > > > do_nothing(); > > > - copied = access_process_vm(current, (unsigned long)dst, do_nothing, > > > + copied = access_process_vm(current, (unsigned long)dst, > > > do_nothing_text, > > > EXEC_SIZE, FOLL_WRITE); > > > if (copied < EXEC_SIZE) > > > return; > > > - pr_info("attempting bad execution at %px\n", func); > > > + pr_info("attempting bad execution at %px\n", dst); > > > + func = setup_function_descriptor(&fdesc, dst); > > > func(); > > > pr_err("FAIL: func returned\n"); > > > } > > > @@ -153,7 +171,8 @@ void lkdtm_EXEC_VMALLOC(void) > > > void lkdtm_EXEC_RODATA(void) > > > { > > > - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); > > > + execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing), > > > > > > + CODE_AS_IS); > > > } > > > void lkdtm_EXEC_USERSPACE(void) > > >
On Sun, Oct 17, 2021 at 02:38:24PM +0200, Christophe Leroy wrote: > execute_location() and execute_user_location() intent > to copy do_nothing() text and execute it at a new location. > However, at the time being it doesn't copy do_nothing() function > but do_nothing() function descriptor which still points to the > original text. So at the end it still executes do_nothing() at > its original location allthough using a copied function descriptor. > > So, fix that by really copying do_nothing() text and build a new > function descriptor by copying do_nothing() function descriptor and > updating the target address with the new location. > > Also fix the displayed addresses by dereferencing do_nothing() > function descriptor. > > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> This looks good. I might rename variables in the future (e.g. to avoid the churn from adding _text) but also, that does help keep it clear. :) Acked-by: Kees Cook <keescook@chromium.org> -Kees > --- > drivers/misc/lkdtm/perms.c | 37 ++++++++++++++++++++++++++++--------- > 1 file changed, 28 insertions(+), 9 deletions(-) > > diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c > index 035fcca441f0..1cf24c4a79e9 100644 > --- a/drivers/misc/lkdtm/perms.c > +++ b/drivers/misc/lkdtm/perms.c > @@ -44,19 +44,34 @@ static noinline void do_overwritten(void) > return; > } > > +static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) > +{ > + if (!have_function_descriptors()) > + return dst; > + > + memcpy(fdesc, do_nothing, sizeof(*fdesc)); > + fdesc->addr = (unsigned long)dst; > + barrier(); > + > + return fdesc; > +} > + > static noinline void execute_location(void *dst, bool write) > { > - void (*func)(void) = dst; > + void (*func)(void); > + func_desc_t fdesc; > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > - pr_info("attempting ok execution at %px\n", do_nothing); > + pr_info("attempting ok execution at %px\n", do_nothing_text); > do_nothing(); > > if (write == CODE_WRITE) { > - memcpy(dst, do_nothing, EXEC_SIZE); > + memcpy(dst, do_nothing_text, EXEC_SIZE); > flush_icache_range((unsigned long)dst, > (unsigned long)dst + EXEC_SIZE); > } > - pr_info("attempting bad execution at %px\n", func); > + pr_info("attempting bad execution at %px\n", dst); > + func = setup_function_descriptor(&fdesc, dst); > func(); > pr_err("FAIL: func returned\n"); > } > @@ -66,16 +81,19 @@ static void execute_user_location(void *dst) > int copied; > > /* Intentionally crossing kernel/user memory boundary. */ > - void (*func)(void) = dst; > + void (*func)(void); > + func_desc_t fdesc; > + void *do_nothing_text = dereference_function_descriptor(do_nothing); > > - pr_info("attempting ok execution at %px\n", do_nothing); > + pr_info("attempting ok execution at %px\n", do_nothing_text); > do_nothing(); > > - copied = access_process_vm(current, (unsigned long)dst, do_nothing, > + copied = access_process_vm(current, (unsigned long)dst, do_nothing_text, > EXEC_SIZE, FOLL_WRITE); > if (copied < EXEC_SIZE) > return; > - pr_info("attempting bad execution at %px\n", func); > + pr_info("attempting bad execution at %px\n", dst); > + func = setup_function_descriptor(&fdesc, dst); > func(); > pr_err("FAIL: func returned\n"); > } > @@ -153,7 +171,8 @@ void lkdtm_EXEC_VMALLOC(void) > > void lkdtm_EXEC_RODATA(void) > { > - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); > + execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing), > + CODE_AS_IS); > } > > void lkdtm_EXEC_USERSPACE(void) > -- > 2.31.1 >
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c index 035fcca441f0..1cf24c4a79e9 100644 --- a/drivers/misc/lkdtm/perms.c +++ b/drivers/misc/lkdtm/perms.c @@ -44,19 +44,34 @@ static noinline void do_overwritten(void) return; } +static void *setup_function_descriptor(func_desc_t *fdesc, void *dst) +{ + if (!have_function_descriptors()) + return dst; + + memcpy(fdesc, do_nothing, sizeof(*fdesc)); + fdesc->addr = (unsigned long)dst; + barrier(); + + return fdesc; +} + static noinline void execute_location(void *dst, bool write) { - void (*func)(void) = dst; + void (*func)(void); + func_desc_t fdesc; + void *do_nothing_text = dereference_function_descriptor(do_nothing); - pr_info("attempting ok execution at %px\n", do_nothing); + pr_info("attempting ok execution at %px\n", do_nothing_text); do_nothing(); if (write == CODE_WRITE) { - memcpy(dst, do_nothing, EXEC_SIZE); + memcpy(dst, do_nothing_text, EXEC_SIZE); flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); } - pr_info("attempting bad execution at %px\n", func); + pr_info("attempting bad execution at %px\n", dst); + func = setup_function_descriptor(&fdesc, dst); func(); pr_err("FAIL: func returned\n"); } @@ -66,16 +81,19 @@ static void execute_user_location(void *dst) int copied; /* Intentionally crossing kernel/user memory boundary. */ - void (*func)(void) = dst; + void (*func)(void); + func_desc_t fdesc; + void *do_nothing_text = dereference_function_descriptor(do_nothing); - pr_info("attempting ok execution at %px\n", do_nothing); + pr_info("attempting ok execution at %px\n", do_nothing_text); do_nothing(); - copied = access_process_vm(current, (unsigned long)dst, do_nothing, + copied = access_process_vm(current, (unsigned long)dst, do_nothing_text, EXEC_SIZE, FOLL_WRITE); if (copied < EXEC_SIZE) return; - pr_info("attempting bad execution at %px\n", func); + pr_info("attempting bad execution at %px\n", dst); + func = setup_function_descriptor(&fdesc, dst); func(); pr_err("FAIL: func returned\n"); } @@ -153,7 +171,8 @@ void lkdtm_EXEC_VMALLOC(void) void lkdtm_EXEC_RODATA(void) { - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); + execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing), + CODE_AS_IS); } void lkdtm_EXEC_USERSPACE(void)
execute_location() and execute_user_location() intent to copy do_nothing() text and execute it at a new location. However, at the time being it doesn't copy do_nothing() function but do_nothing() function descriptor which still points to the original text. So at the end it still executes do_nothing() at its original location allthough using a copied function descriptor. So, fix that by really copying do_nothing() text and build a new function descriptor by copying do_nothing() function descriptor and updating the target address with the new location. Also fix the displayed addresses by dereferencing do_nothing() function descriptor. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- drivers/misc/lkdtm/perms.c | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-)