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PROT_WRITE implies PROT_READ on x86

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Zhang Junyang 2024-10-16 18:07:01 +08:00 committed by Tate, Hongliang Tian
parent 6757b39c13
commit 1fe0a138f9
2 changed files with 19 additions and 0 deletions
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9
kernel/src/syscall/mmap.rs
View File

@ -74,6 +74,15 @@ fn do_sys_mmap(
return_errno_with_message!(Errno::ENOMEM, "mmap (addr + len) too large"); return_errno_with_message!(Errno::ENOMEM, "mmap (addr + len) too large");
} }
// On x86, `PROT_WRITE` implies `PROT_READ`.
// <https://man7.org/linux/man-pages/man2/mmap.2.html>
#[cfg(target_arch = "x86_64")]
let vm_perms = if !vm_perms.contains(VmPerms::READ) && vm_perms.contains(VmPerms::WRITE) {
vm_perms | VmPerms::READ
} else {
vm_perms
};
let root_vmar = ctx.process.root_vmar(); let root_vmar = ctx.process.root_vmar();
let vm_map_options = { let vm_map_options = {
let mut options = root_vmar.new_map(len, vm_perms)?; let mut options = root_vmar.new_map(len, vm_perms)?;

10
kernel/src/syscall/mprotect.rs
View File

@ -32,6 +32,16 @@ pub fn sys_mprotect(addr: Vaddr, len: usize, perms: u64, ctx: &Context) -> Resul
"integer overflow when (addr + len)", "integer overflow when (addr + len)",
))?; ))?;
let range = addr..end; let range = addr..end;
// On x86, `PROT_WRITE` implies `PROT_READ`.
// <https://man7.org/linux/man-pages/man2/mprotect.2.html>
#[cfg(target_arch = "x86_64")]
let vm_perms = if !vm_perms.contains(VmPerms::READ) && vm_perms.contains(VmPerms::WRITE) {
vm_perms | VmPerms::READ
} else {
vm_perms
};
root_vmar.protect(vm_perms, range)?; root_vmar.protect(vm_perms, range)?;
Ok(SyscallReturn::Return(0)) Ok(SyscallReturn::Return(0))
} }