| Message ID | 20190613111335.7645-12-cristian.marussi@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add arm64/signal initial kselftest support | expand |
On Thu, Jun 13, 2019 at 12:13:33PM +0100, Cristian Marussi wrote: > Added a simple fake_sigreturn testcase which builds a ucontext_t > with a badly sized header and place it onto the stack. > Expects a SIGSEGV on test PASS. > > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> > --- > .../arm64/signal/testcases/.gitignore | 1 + > .../testcases/fake_sigreturn_bad_size.c | 40 +++++++++++++++++++ > 2 files changed, 41 insertions(+) > create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c > > diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore > index c353b7bd899d..9ad1735e0018 100644 > --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore > +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore > @@ -8,3 +8,4 @@ mangle_pstate_invalid_mode_el3 > mangle_pstate_ssbs_regs > fake_sigreturn_misaligned > fake_sigreturn_bad_magic > +fake_sigreturn_bad_size > diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c > new file mode 100644 > index 000000000000..d54f79d63bf6 > --- /dev/null > +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c > @@ -0,0 +1,40 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (C) 2019 ARM Limited */ > + > +#include <asm/sigcontext.h> > +#include <ucontext.h> > + > +#include "test_signals_utils.h" > +#include "testcases.h" > + > +struct a_sigframe sf; > + > +static int fake_sigreturn_bad_size_run(struct tdescr *td, > + siginfo_t *si, ucontext_t *uc) > +{ > + struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf); > + > + /* just to fill the ucontext_t with something real */ > + if (!get_current_context(td, &sf.uc)) > + return 1; > + > + /* Tampering size to an unplausible number should cause a SEGV */ > + head = get_terminator(head, GET_SF_RESV_SIZE(sf), NULL); > + if (head) { > + head->magic = ESR_MAGIC; Add a comment to say why we're using this magic? > + head->size = GET_SF_RESV_SIZE(sf) * 2; If we have extra_context, this might not be an invalid size, because extra_context can be much larger than sizeof(__reserved) ... but also we will overrun anyway, because extra_context should already be only just large enough to accommodate the original terminator. As with the previous test, we should probably throw away the extra_context record (if any) and replace it with this new record. We should check the actual boundary condition here, rather than just testing with a giant size: we want to make the kernel detects any overrun, however small. We should also write a valid terminator after the new record, so that we know the kernel is detecting the size overrun instead of rejecting the next record because it is garbage. > + > + ASSERT_BAD_CONTEXT(&sf.uc); > + fake_sigreturn(&sf, sizeof(sf), 16); > + } > + > + return 1; > +} [...] Cheers ---Dave
Hi On 6/21/19 11:36 AM, Dave Martin wrote: > On Thu, Jun 13, 2019 at 12:13:33PM +0100, Cristian Marussi wrote: >> Added a simple fake_sigreturn testcase which builds a ucontext_t >> with a badly sized header and place it onto the stack. >> Expects a SIGSEGV on test PASS. >> >> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> >> --- >> .../arm64/signal/testcases/.gitignore | 1 + >> .../testcases/fake_sigreturn_bad_size.c | 40 +++++++++++++++++++ >> 2 files changed, 41 insertions(+) >> create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> >> diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore >> index c353b7bd899d..9ad1735e0018 100644 >> --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore >> +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore >> @@ -8,3 +8,4 @@ mangle_pstate_invalid_mode_el3 >> mangle_pstate_ssbs_regs >> fake_sigreturn_misaligned >> fake_sigreturn_bad_magic >> +fake_sigreturn_bad_size >> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> new file mode 100644 >> index 000000000000..d54f79d63bf6 >> --- /dev/null >> +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c >> @@ -0,0 +1,40 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* Copyright (C) 2019 ARM Limited */ >> + >> +#include <asm/sigcontext.h> >> +#include <ucontext.h> >> + >> +#include "test_signals_utils.h" >> +#include "testcases.h" >> + >> +struct a_sigframe sf; >> + >> +static int fake_sigreturn_bad_size_run(struct tdescr *td, >> + siginfo_t *si, ucontext_t *uc) >> +{ >> + struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf); >> + >> + /* just to fill the ucontext_t with something real */ >> + if (!get_current_context(td, &sf.uc)) >> + return 1; >> + >> + /* Tampering size to an unplausible number should cause a SEGV */ >> + head = get_terminator(head, GET_SF_RESV_SIZE(sf), NULL); >> + if (head) { >> + head->magic = ESR_MAGIC; > > Add a comment to say why we're using this magic? > >> + head->size = GET_SF_RESV_SIZE(sf) * 2; > > If we have extra_context, this might not be an invalid size, because > extra_context can be much larger than sizeof(__reserved) ... but also > we will overrun anyway, because extra_context should already be only > just large enough to accommodate the original terminator. > > As with the previous test, we should probably throw away the > extra_context record (if any) and replace it with this new record. > > We should check the actual boundary condition here, rather than just > testing with a giant size: we want to make the kernel detects any > overrun, however small. > > We should also write a valid terminator after the new record, so > that we know the kernel is detecting the size overrun instead of > rejecting the next record because it is garbage. > Fixed in V2: throwing away the extra when needed, and adding a bogus ESR_MAGIC with a bogus size, large enough to fit all the remaining free __reserved (- NULL terminator space) + 16 bytes (to be still aligned and crashing out on an overrun of the least minimum size) and terminated with another NULL Cristian >> + >> + ASSERT_BAD_CONTEXT(&sf.uc); >> + fake_sigreturn(&sf, sizeof(sf), 16); >> + } >> + >> + return 1; >> +} > > [...] > > Cheers > ---Dave >
diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore index c353b7bd899d..9ad1735e0018 100644 --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore @@ -8,3 +8,4 @@ mangle_pstate_invalid_mode_el3 mangle_pstate_ssbs_regs fake_sigreturn_misaligned fake_sigreturn_bad_magic +fake_sigreturn_bad_size diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c new file mode 100644 index 000000000000..d54f79d63bf6 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2019 ARM Limited */ + +#include <asm/sigcontext.h> +#include <ucontext.h> + +#include "test_signals_utils.h" +#include "testcases.h" + +struct a_sigframe sf; + +static int fake_sigreturn_bad_size_run(struct tdescr *td, + siginfo_t *si, ucontext_t *uc) +{ + struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf); + + /* just to fill the ucontext_t with something real */ + if (!get_current_context(td, &sf.uc)) + return 1; + + /* Tampering size to an unplausible number should cause a SEGV */ + head = get_terminator(head, GET_SF_RESV_SIZE(sf), NULL); + if (head) { + head->magic = ESR_MAGIC; + head->size = GET_SF_RESV_SIZE(sf) * 2; + + ASSERT_BAD_CONTEXT(&sf.uc); + fake_sigreturn(&sf, sizeof(sf), 16); + } + + return 1; +} + +struct tdescr tde = { + .name = "FAKE_SIGRETURN_BAD_SIZE", + .descr = "Triggers a fake sigreturn with a sigframe including a bad sized head on __reserved", + .sig_ok = SIGSEGV, + .timeout = 3, + .run = fake_sigreturn_bad_size_run, +};
Added a simple fake_sigreturn testcase which builds a ucontext_t with a badly sized header and place it onto the stack. Expects a SIGSEGV on test PASS. Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> --- .../arm64/signal/testcases/.gitignore | 1 + .../testcases/fake_sigreturn_bad_size.c | 40 +++++++++++++++++++ 2 files changed, 41 insertions(+) create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c