* [PATCH 0/2] selftests/x86: fsgsbase test updates
@ 2020-08-26 17:00 Andy Lutomirski
2020-08-26 17:00 ` [PATCH 1/2] selftests/x86/fsgsbase: Reap a forgotten child Andy Lutomirski
2020-08-26 17:00 ` [PATCH 2/2] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS Andy Lutomirski
0 siblings, 2 replies; 5+ messages in thread
From: Andy Lutomirski @ 2020-08-26 17:00 UTC (permalink / raw)
To: x86; +Cc: LKML, Andy Lutomirski
This fixes a minor bug and adds a test for the recent NULL pointer
dereference.
Andy Lutomirski (2):
selftests/x86/fsgsbase: Reap a forgotten child
selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid
LDT GS
tools/testing/selftests/x86/fsgsbase.c | 68 ++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
--
2.25.4
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 1/2] selftests/x86/fsgsbase: Reap a forgotten child 2020-08-26 17:00 [PATCH 0/2] selftests/x86: fsgsbase test updates Andy Lutomirski @ 2020-08-26 17:00 ` Andy Lutomirski 2020-08-26 19:02 ` [tip: x86/fsgsbase] " tip-bot2 for Andy Lutomirski 2020-08-26 17:00 ` [PATCH 2/2] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS Andy Lutomirski 1 sibling, 1 reply; 5+ messages in thread From: Andy Lutomirski @ 2020-08-26 17:00 UTC (permalink / raw) To: x86; +Cc: LKML, Andy Lutomirski The ptrace() test forgot to reap its child. Reap it. Signed-off-by: Andy Lutomirski <luto@kernel.org> --- tools/testing/selftests/x86/fsgsbase.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 998319553523..0056e2597f53 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -517,6 +517,9 @@ static void test_ptrace_write_gsbase(void) END: ptrace(PTRACE_CONT, child, NULL, NULL); + wait(&status); + if (!WIFEXITED(status)) + printf("[WARN]\tChild didn't exit cleanly.\n"); } int main() -- 2.25.4 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [tip: x86/fsgsbase] selftests/x86/fsgsbase: Reap a forgotten child 2020-08-26 17:00 ` [PATCH 1/2] selftests/x86/fsgsbase: Reap a forgotten child Andy Lutomirski @ 2020-08-26 19:02 ` tip-bot2 for Andy Lutomirski 0 siblings, 0 replies; 5+ messages in thread From: tip-bot2 for Andy Lutomirski @ 2020-08-26 19:02 UTC (permalink / raw) To: linux-tip-commits; +Cc: Andy Lutomirski, Ingo Molnar, x86, LKML The following commit has been merged into the x86/fsgsbase branch of tip: Commit-ID: ab2dd173330a3f07142e68cd65682205036cd00f Gitweb: https://git.kernel.org/tip/ab2dd173330a3f07142e68cd65682205036cd00f Author: Andy Lutomirski <luto@kernel.org> AuthorDate: Wed, 26 Aug 2020 10:00:45 -07:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Wed, 26 Aug 2020 20:54:17 +02:00 selftests/x86/fsgsbase: Reap a forgotten child The ptrace() test forgot to reap its child. Reap it. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/e7700a503f30e79ab35a63103938a19893dbeff2.1598461151.git.luto@kernel.org --- tools/testing/selftests/x86/fsgsbase.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 9983195..0056e25 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -517,6 +517,9 @@ static void test_ptrace_write_gsbase(void) END: ptrace(PTRACE_CONT, child, NULL, NULL); + wait(&status); + if (!WIFEXITED(status)) + printf("[WARN]\tChild didn't exit cleanly.\n"); } int main() ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS 2020-08-26 17:00 [PATCH 0/2] selftests/x86: fsgsbase test updates Andy Lutomirski 2020-08-26 17:00 ` [PATCH 1/2] selftests/x86/fsgsbase: Reap a forgotten child Andy Lutomirski @ 2020-08-26 17:00 ` Andy Lutomirski 2020-08-26 19:02 ` [tip: x86/fsgsbase] " tip-bot2 for Andy Lutomirski 1 sibling, 1 reply; 5+ messages in thread From: Andy Lutomirski @ 2020-08-26 17:00 UTC (permalink / raw) To: x86; +Cc: LKML, Andy Lutomirski, stable This tesst commit 8ab49526b53d ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task"). Unpatched kernels will OOPS. Cc: stable@vger.kernel.org Signed-off-by: Andy Lutomirski <luto@kernel.org> --- tools/testing/selftests/x86/fsgsbase.c | 65 ++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 0056e2597f53..7161cfc2e60b 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -443,6 +443,68 @@ static void test_unexpected_base(void) #define USER_REGS_OFFSET(r) offsetof(struct user_regs_struct, r) +static void test_ptrace_write_gs_read_base(void) +{ + int status; + pid_t child = fork(); + + if (child < 0) + err(1, "fork"); + + if (child == 0) { + printf("[RUN]\tPTRACE_POKE GS, read GSBASE back\n"); + + printf("[RUN]\tARCH_SET_GS to 1\n"); + if (syscall(SYS_arch_prctl, ARCH_SET_GS, 1) != 0) + err(1, "ARCH_SET_GS"); + + if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) + err(1, "PTRACE_TRACEME"); + + raise(SIGTRAP); + _exit(0); + } + + wait(&status); + + if (WSTOPSIG(status) == SIGTRAP) { + unsigned long base; + unsigned long gs_offset = USER_REGS_OFFSET(gs); + unsigned long base_offset = USER_REGS_OFFSET(gs_base); + + /* Read the initial base. It should be 1. */ + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); + if (base == 1) { + printf("[OK]\tGSBASE started at 1\n"); + } else { + nerrs++; + printf("[FAIL]\tGSBASE started at 0x%lx\n", base); + } + + printf("[RUN]\tSet GS = 0x7, read GSBASE\n"); + + /* Poke an LDT selector into GS. */ + if (ptrace(PTRACE_POKEUSER, child, gs_offset, 0x7) != 0) + err(1, "PTRACE_POKEUSER"); + + /* And read the base. */ + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); + + if (base == 0 || base == 1) { + printf("[OK]\tGSBASE reads as 0x%lx with invalid GS\n", base); + } else { + nerrs++; + printf("[FAIL]\tGSBASE=0x%lx (should be 0 or 1)\n", base); + } + } + + ptrace(PTRACE_CONT, child, NULL, NULL); + + wait(&status); + if (!WIFEXITED(status)) + printf("[WARN]\tChild didn't exit cleanly.\n"); +} + static void test_ptrace_write_gsbase(void) { int status; @@ -529,6 +591,9 @@ int main() shared_scratch = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); + /* Do these tests before we have an LDT. */ + test_ptrace_write_gs_read_base(); + /* Probe FSGSBASE */ sethandler(SIGILL, sigill, 0); if (sigsetjmp(jmpbuf, 1) == 0) { -- 2.25.4 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [tip: x86/fsgsbase] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS 2020-08-26 17:00 ` [PATCH 2/2] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS Andy Lutomirski @ 2020-08-26 19:02 ` tip-bot2 for Andy Lutomirski 0 siblings, 0 replies; 5+ messages in thread From: tip-bot2 for Andy Lutomirski @ 2020-08-26 19:02 UTC (permalink / raw) To: linux-tip-commits; +Cc: Andy Lutomirski, Ingo Molnar, stable, x86, LKML The following commit has been merged into the x86/fsgsbase branch of tip: Commit-ID: 1b9abd1755ad947d7c9913e92e7837b533124c90 Gitweb: https://git.kernel.org/tip/1b9abd1755ad947d7c9913e92e7837b533124c90 Author: Andy Lutomirski <luto@kernel.org> AuthorDate: Wed, 26 Aug 2020 10:00:46 -07:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Wed, 26 Aug 2020 20:54:18 +02:00 selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS This tests commit: 8ab49526b53d ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task") Unpatched kernels will OOPS. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/c618ae86d1f757e01b1a8e79869f553cb88acf9a.1598461151.git.luto@kernel.org --- tools/testing/selftests/x86/fsgsbase.c | 65 +++++++++++++++++++++++++- 1 file changed, 65 insertions(+) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 0056e25..7161cfc 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -443,6 +443,68 @@ static void test_unexpected_base(void) #define USER_REGS_OFFSET(r) offsetof(struct user_regs_struct, r) +static void test_ptrace_write_gs_read_base(void) +{ + int status; + pid_t child = fork(); + + if (child < 0) + err(1, "fork"); + + if (child == 0) { + printf("[RUN]\tPTRACE_POKE GS, read GSBASE back\n"); + + printf("[RUN]\tARCH_SET_GS to 1\n"); + if (syscall(SYS_arch_prctl, ARCH_SET_GS, 1) != 0) + err(1, "ARCH_SET_GS"); + + if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) + err(1, "PTRACE_TRACEME"); + + raise(SIGTRAP); + _exit(0); + } + + wait(&status); + + if (WSTOPSIG(status) == SIGTRAP) { + unsigned long base; + unsigned long gs_offset = USER_REGS_OFFSET(gs); + unsigned long base_offset = USER_REGS_OFFSET(gs_base); + + /* Read the initial base. It should be 1. */ + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); + if (base == 1) { + printf("[OK]\tGSBASE started at 1\n"); + } else { + nerrs++; + printf("[FAIL]\tGSBASE started at 0x%lx\n", base); + } + + printf("[RUN]\tSet GS = 0x7, read GSBASE\n"); + + /* Poke an LDT selector into GS. */ + if (ptrace(PTRACE_POKEUSER, child, gs_offset, 0x7) != 0) + err(1, "PTRACE_POKEUSER"); + + /* And read the base. */ + base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL); + + if (base == 0 || base == 1) { + printf("[OK]\tGSBASE reads as 0x%lx with invalid GS\n", base); + } else { + nerrs++; + printf("[FAIL]\tGSBASE=0x%lx (should be 0 or 1)\n", base); + } + } + + ptrace(PTRACE_CONT, child, NULL, NULL); + + wait(&status); + if (!WIFEXITED(status)) + printf("[WARN]\tChild didn't exit cleanly.\n"); +} + static void test_ptrace_write_gsbase(void) { int status; @@ -529,6 +591,9 @@ int main() shared_scratch = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); + /* Do these tests before we have an LDT. */ + test_ptrace_write_gs_read_base(); + /* Probe FSGSBASE */ sethandler(SIGILL, sigill, 0); if (sigsetjmp(jmpbuf, 1) == 0) { ^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-08-26 19:03 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2020-08-26 17:00 [PATCH 0/2] selftests/x86: fsgsbase test updates Andy Lutomirski 2020-08-26 17:00 ` [PATCH 1/2] selftests/x86/fsgsbase: Reap a forgotten child Andy Lutomirski 2020-08-26 19:02 ` [tip: x86/fsgsbase] " tip-bot2 for Andy Lutomirski 2020-08-26 17:00 ` [PATCH 2/2] selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS Andy Lutomirski 2020-08-26 19:02 ` [tip: x86/fsgsbase] " tip-bot2 for Andy Lutomirski
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