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Diffstat (limited to 'gitlab/issues/target_missing/host_missing/accel_missing/2390.toml')
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1 files changed, 0 insertions, 71 deletions
diff --git a/gitlab/issues/target_missing/host_missing/accel_missing/2390.toml b/gitlab/issues/target_missing/host_missing/accel_missing/2390.toml deleted file mode 100644 index 5bd6c051..00000000 --- a/gitlab/issues/target_missing/host_missing/accel_missing/2390.toml +++ /dev/null @@ -1,71 +0,0 @@ -id = 2390 -title = "linux-user: Qemu handles `getsockopt` with NULL `optval` incorrectly" -state = "opened" -created_at = "2024-06-13T14:20:38.278Z" -closed_at = "n/a" -labels = ["linux-user"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/2390" -host-os = "Ubuntu 22.04.3 LTS" -host-arch = "x86_64" -qemu-version = "6.2.0" -guest-os = "Ubuntu 22.04.3 LTS" -guest-arch = "RISC-V 64" -description = """In short call to `getsockopt(_, SOL_TCP, TCP_KEEPIDLE, NULL, _)` behaves differently on RISC-V Qemu than on x64 Linux. -On Linux syscall returns 0, but on Qemu it fails with `"Bad address"`. -Apparently Qemu `getsockopt` implementation is more conservative about NULL `optval` argument than kernel implementation. However man permits passing NULL [link](https://man7.org/linux/man-pages/man2/setsockopt.2.html): - -> For getsockopt(), optlen is a value-result argument, initially - containing the size of the buffer pointed to by optval, and - modified on return to indicate the actual size of the value - returned. **If no option value is to be supplied** or returned, - **optval may be NULL.**" - -For me it sounds like accepting NULL without error (and x64 confirms that interpretation).""" -reproduce = """1. Use below toy program `getsockopt.c` and compile it without optimizations like: -``` - gcc -Wall -W -std=gnu11 -pedantic getsockopt.c -o getsockopt -``` - -``` -#include <stdlib.h> -#include <unistd.h> -#include <errno.h> -#include <stdio.h> -#include <netinet/in.h> -#include <sys/socket.h> -#include <netinet/tcp.h> - -static void fail_on_error(int error, const char *msg) { - if (error < 0) { - perror(msg); - exit(errno); - } -} - -int main(int argc, char **argv) { - int socketfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP); - fail_on_error(socketfd, "socket error"); - uint8_t *option_value = NULL; - int32_t len = 0; - int32_t *option_len = &len; - socklen_t opt_len = (socklen_t)*option_len; - int status = getsockopt(socketfd, SOL_TCP, TCP_KEEPIDLE, option_value, &opt_len); - fail_on_error(status, "getsockopt error"); - return 0; -} -``` - - -2. Run program on Qemu and compare output with output from x64 build. In my case it looks like: -``` -root@57646f544f3a:/runtime/programs# ./getsockopt-x64 -root@57646f544f3a:/runtime/programs# ./getsockopt-riscv -getsockopt error: Bad address -```""" -additional = """I don't think issue is platform specific assuming Qemu `getsockopt` implementation that is actually running is here: -[link](https://github.com/qemu/qemu/blob/master/linux-user/syscall.c#L2522) - -Looking at sources, I'm not sure why Qemu can't simply forward everything to kernel space -instead doing extra sanity checks together with `optval` dereference attempt that eventually fails in one of `put_user*_` function: [link](https://github.com/qemu/qemu/blob/master/linux-user/syscall.c#L2753) - -Anyway, I think that interpretation of man quote is rather straightforward and Qemu `getsockopt` implementation should follow it.""" |