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Kernel: Send SIGBUS to threads that use after valid Inode mmaped range

Browse source 
According to Dr. POSIX, we should allow to call mmap on inodes even on
ranges that currently don't map to any actual data. Trying to read or
write to those ranges should result in SIGBUS being sent to the thread
that did violating memory access.
This commit is contained in:
Liav A 2022-08-07 22:08:52 +03:00 • committed by Idan Horowitz
parent 3ad0e1a1d5
commit 0c675192c9
4 changed files with 57 additions and 33 deletions
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71
Kernel/Arch/x86/common/Interrupts.cpp
View file

@ -317,7 +317,7 @@ void page_fault_handler(TrapFrame* trap)
PageFault fault { regs.exception_code, VirtualAddress { fault_address } };
auto response = MM.handle_page_fault(fault);
if (response == PageFaultResponse::ShouldCrash || response == PageFaultResponse::OutOfMemory) {
if (response == PageFaultResponse::ShouldCrash || response == PageFaultResponse::OutOfMemory || response == PageFaultResponse::BusError) {
if (faulted_in_kernel && handle_safe_access_fault(regs, fault_address)) {
// If this would be a ring0 (kernel) fault and the fault was triggered by
// safe_memcpy, safe_strnlen, or safe_memset then we resume execution at
@ -325,6 +325,11 @@ void page_fault_handler(TrapFrame* trap)
return;
}
if (response == PageFaultResponse::BusError && current_thread->has_signal_handler(SIGBUS)) {
current_thread->send_urgent_signal_to_self(SIGBUS);
return;
}
if (response != PageFaultResponse::OutOfMemory && current_thread) {
if (current_thread->has_signal_handler(SIGSEGV)) {
current_thread->send_urgent_signal_to_self(SIGSEGV);
@ -341,36 +346,40 @@ void page_fault_handler(TrapFrame* trap)
constexpr FlatPtr free_scrub_pattern = explode_byte(FREE_SCRUB_BYTE);
constexpr FlatPtr kmalloc_scrub_pattern = explode_byte(KMALLOC_SCRUB_BYTE);
constexpr FlatPtr kfree_scrub_pattern = explode_byte(KFREE_SCRUB_BYTE);
if ((fault_address & 0xffff0000) == (malloc_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be uninitialized malloc() memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (free_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be recently free()'d memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (kmalloc_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be uninitialized kmalloc() memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (kfree_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be recently kfree()'d memory", VirtualAddress(fault_address));
} else if (fault_address < 4096) {
dbgln("Note: Address {} looks like a possible nullptr dereference", VirtualAddress(fault_address));
} else if constexpr (SANITIZE_PTRS) {
constexpr FlatPtr refptr_scrub_pattern = explode_byte(REFPTR_SCRUB_BYTE);
constexpr FlatPtr nonnullrefptr_scrub_pattern = explode_byte(NONNULLREFPTR_SCRUB_BYTE);
constexpr FlatPtr ownptr_scrub_pattern = explode_byte(OWNPTR_SCRUB_BYTE);
constexpr FlatPtr nonnullownptr_scrub_pattern = explode_byte(NONNULLOWNPTR_SCRUB_BYTE);
constexpr FlatPtr lockrefptr_scrub_pattern = explode_byte(LOCKREFPTR_SCRUB_BYTE);
constexpr FlatPtr nonnulllockrefptr_scrub_pattern = explode_byte(NONNULLLOCKREFPTR_SCRUB_BYTE);
if (response == PageFaultResponse::BusError) {
dbgln("Note: Address {} is an access to undefined memory range of a Inode-backed VMObject", VirtualAddress(fault_address));
} else {
if ((fault_address & 0xffff0000) == (malloc_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be uninitialized malloc() memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (free_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be recently free()'d memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (kmalloc_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be uninitialized kmalloc() memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (kfree_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be recently kfree()'d memory", VirtualAddress(fault_address));
} else if (fault_address < 4096) {
dbgln("Note: Address {} looks like a possible nullptr dereference", VirtualAddress(fault_address));
} else if constexpr (SANITIZE_PTRS) {
constexpr FlatPtr refptr_scrub_pattern = explode_byte(REFPTR_SCRUB_BYTE);
constexpr FlatPtr nonnullrefptr_scrub_pattern = explode_byte(NONNULLREFPTR_SCRUB_BYTE);
constexpr FlatPtr ownptr_scrub_pattern = explode_byte(OWNPTR_SCRUB_BYTE);
constexpr FlatPtr nonnullownptr_scrub_pattern = explode_byte(NONNULLOWNPTR_SCRUB_BYTE);
constexpr FlatPtr lockrefptr_scrub_pattern = explode_byte(LOCKREFPTR_SCRUB_BYTE);
constexpr FlatPtr nonnulllockrefptr_scrub_pattern = explode_byte(NONNULLLOCKREFPTR_SCRUB_BYTE);
if ((fault_address & 0xffff0000) == (refptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed LockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnullrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullLockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (ownptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed OwnPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnullownptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullOwnPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (lockrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed LockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnulllockrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullLockRefPtr", VirtualAddress(fault_address));
if ((fault_address & 0xffff0000) == (refptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed LockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnullrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullLockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (ownptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed OwnPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnullownptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullOwnPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (lockrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed LockRefPtr", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (nonnulllockrefptr_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be a recently destroyed NonnullLockRefPtr", VirtualAddress(fault_address));
}
}
}
@ -390,6 +399,8 @@ void page_fault_handler(TrapFrame* trap)
}
}
if (response == PageFaultResponse::BusError)
return handle_crash(regs, "Page Fault (Bus Error)", SIGBUS, false);
return handle_crash(regs, "Page Fault", SIGSEGV, response == PageFaultResponse::OutOfMemory);
} else if (response == PageFaultResponse::Continue) {
dbgln_if(PAGE_FAULT_DEBUG, "Continuing after resolved page fault");