resolv: Track single-request fallback via _res._flags (bug 31476)

This avoids changing _res.options, which inteferes with change
detection as part of automatic reloading of /etc/resolv.conf.

Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit 868ab8923a)
This commit is contained in:
Florian Weimer 2024-06-13 18:56:30 +02:00
parent df808340fd
commit 7285630e0e
3 changed files with 10 additions and 5 deletions

1
NEWS
View File

@ -166,6 +166,7 @@ The following bugs are resolved with this release:
[30843] potential use-after-free in getcanonname (CVE-2023-4806) [30843] potential use-after-free in getcanonname (CVE-2023-4806)
[31184] FAIL: elf/tst-tlsgap [31184] FAIL: elf/tst-tlsgap
[31185] Incorrect thread point access in _dl_tlsdesc_undefweak and _dl_tlsdesc_dynamic [31185] Incorrect thread point access in _dl_tlsdesc_undefweak and _dl_tlsdesc_dynamic
[31476] resolv: Track single-request fallback via _res._flags
[31890] resolv: Allow short error responses to match any DNS query [31890] resolv: Allow short error responses to match any DNS query

View File

@ -942,9 +942,11 @@ send_dg(res_state statp,
seconds /= statp->nscount; seconds /= statp->nscount;
if (seconds <= 0) if (seconds <= 0)
seconds = 1; seconds = 1;
bool single_request_reopen = (statp->options & RES_SNGLKUPREOP) != 0; bool single_request_reopen = ((statp->options & RES_SNGLKUPREOP)
bool single_request = (((statp->options & RES_SNGLKUP) != 0) || (statp->_flags & RES_F_SNGLKUPREOP));
| single_request_reopen); bool single_request = ((statp->options & RES_SNGLKUP)
|| (statp->_flags & RES_F_SNGLKUP)
|| single_request_reopen);
int save_gotsomewhere = *gotsomewhere; int save_gotsomewhere = *gotsomewhere;
int retval; int retval;
@ -1001,14 +1003,14 @@ send_dg(res_state statp,
have received the first answer. */ have received the first answer. */
if (!single_request) if (!single_request)
{ {
statp->options |= RES_SNGLKUP; statp->_flags |= RES_F_SNGLKUP;
single_request = true; single_request = true;
*gotsomewhere = save_gotsomewhere; *gotsomewhere = save_gotsomewhere;
goto retry; goto retry;
} }
else if (!single_request_reopen) else if (!single_request_reopen)
{ {
statp->options |= RES_SNGLKUPREOP; statp->_flags |= RES_F_SNGLKUPREOP;
single_request_reopen = true; single_request_reopen = true;
*gotsomewhere = save_gotsomewhere; *gotsomewhere = save_gotsomewhere;
__res_iclose (statp, false); __res_iclose (statp, false);

View File

@ -26,6 +26,8 @@
#define RES_F_VC 0x00000001 /* Socket is TCP. */ #define RES_F_VC 0x00000001 /* Socket is TCP. */
#define RES_F_CONN 0x00000002 /* Socket is connected. */ #define RES_F_CONN 0x00000002 /* Socket is connected. */
#define RES_F_EDNS0ERR 0x00000004 /* EDNS0 caused errors. */ #define RES_F_EDNS0ERR 0x00000004 /* EDNS0 caused errors. */
#define RES_F_SNGLKUP 0x00200000 /* Private version of RES_SNGLKUP. */
#define RES_F_SNGLKUPREOP 0x00400000 /* Private version of RES_SNGLKUPREOP. */
/* Legacy function. This needs to be removed once all NSS modules /* Legacy function. This needs to be removed once all NSS modules
have been adjusted. */ have been adjusted. */