auth: Panic: file oauth2-request.c assertion failed

Urban Loesch bind at enas.net
Wed Dec 7 13:49:16 UTC 2022


Hi,

I'm running a postfix smtp relay server on which users are getting authenticated trough sasl via the dovecot authentication service. This works 
without problems.

Recently I extended my configuration to authenticate users with the PLAIN mechanism against Azure AD B2C with oauth2 in the future.
Important to mention is that currently no users are stored in Azure B2C. I only prepared the hole configuration and authentiucation falls back to 
mysql database.

Now sometimes I get the error below in my logs (not permanently):
...
Dec  7 11:36:49 relay-out1 dovecot: auth: Panic: file oauth2-request.c: line 201 (oauth2_request_start): assertion failed: 
(oauth2_valid_token(input->token))
Dec  7 11:36:49 relay-out1 dovecot: auth: Error: Raw backtrace: /usr/lib/dovecot/libdovecot.so.0(backtrace_append+0x3d) [0x7f399402e62d] -> 
/usr/lib/dovecot/libdovecot.so.0(backtrace_get+0x1e) [0x7f399402e74e] -> /usr/lib/dovecot/libdovecot.so.0(+0x1006eb) [0x7f399403b6eb] -> 
/usr/lib/dovecot/libdovecot.so.0(+0x100781) [0x7f399403b781] -> /usr/lib/dovecot/libdovecot.so.0(+0x54b7c) [0x7f3993f8fb7c] -> 
/usr/lib/dovecot/libdovecot.so.0(+0x4605a) [0x7f3993f8105a] -> /usr/lib/dovecot/libdovecot.so.0(oauth2_passwd_grant_start+0xfa) [0x7f3993f9870a] -> 
dovecot/auth(db_oauth2_lookup+0x2ca) [0x560d0804368a] -> dovecot/auth(auth_request_default_verify_plain_continue+0x2d6) [0x560d08026436] -> 
dovecot/auth(auth_policy_check+0x2b) [0x560d0802071b] -> dovecot/auth(+0x29f72) [0x560d0802ff72] -> 
dovecot/auth(auth_request_handler_auth_continue+0xf7) [0x560d0802a197] -> dovecot/auth(+0x16c62) [0x560d0801cc62] -> 
/usr/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x69) [0x7f3994051c29] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x131) 
[0x7f3994053251] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x4c) [0x7f3994051ccc] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) 
[0x7f3994051e50] -> /usr/lib/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f3993fc4df3] -> dovecot/auth(main+0x415) [0x560d0801abf5] -> 
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7f3993cee09b] -> dovecot/auth(_start+0x2a) [0x560d0801ad8a]
...


After the error above postfix says the connection to the authentication server was lost:
...
Dec  7 11:36:49 relay-out1 rolrelayout1/smtpd[1655601]: warning: domain.com[12.12.12.12]: SASL LOGIN authentication failed: Connection lost to 
authentication server
...


I was able to make a core dump.
...
# gdb /usr/lib/dovecot/auth core.auth.1654357.1670409409
GNU gdb (Debian 8.2.1-2+b3) 8.2.1
...
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /usr/lib/dovecot/auth...Reading symbols from /usr/lib/debug/.build-id/bc/f14ed9cc2dda3ee9565fbd7ccd835460008438.debug...done.
done.
[New LWP 1654357]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `dovecot/auth'.
Program terminated with signal SIGABRT, Aborted.
#0  __GI_raise (sig=sig at entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
50	../sysdeps/unix/sysv/linux/raise.c: Datei oder Verzeichnis nicht gefunden.
(gdb) bt full
#0  __GI_raise (sig=sig at entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
         set = {__val = {0, 1415, 1416, 94613970086496, 10, 139885273538955, 155, 139885273347109, 140724590457408, 118, 206158430224, 
140724590457744, 140724590457536, 16888407779496842752, 94613970086472, 139885273131758}}
         pid = <optimized out>
         tid = <optimized out>
         ret = <optimized out>
#1  0x00007f3993cec535 in __GI_abort () at abort.c:79
         save_stage = 1
         act = {__sigaction_handler = {sa_handler = 0x73f, sa_sigaction = 0x73f}, sa_mask = {__val = {1024, 18446744073709551615, 94613971926672, 
94613971631792, 139885273108347, 94613970084312, 139885273090236, 94613970084312,
               16888407779496842752, 94613970084288, 139885273346402, 140724590457744, 94613970084312, 140724590457744, 139885273346761, 
94613970084312}}, sa_flags = -1811749030, sa_restorer = 0x5}
         sigs = {__val = {32, 0 <repeats 15 times>}}
#2  0x00007f3993f8feaf in default_fatal_finish (status=0, type=LOG_TYPE_PANIC) at failures.c:465
         backtrace = 0x560d0813e220 "/usr/lib/dovecot/libdovecot.so.0(backtrace_append+0x3d) [0x7f399402e62d] -> 
/usr/lib/dovecot/libdovecot.so.0(backtrace_get+0x1e) [0x7f399402e74e] -> /usr/lib/dovecot/libdovecot.so.0(+0x1006eb) [0x7f39"...
         backtrace = <optimized out>
         recursed = 0
#3  fatal_handler_real (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:477
         status = 0
#4  0x00007f399403b781 in i_internal_fatal_handler (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:879
No locals.
#5  0x00007f3993f8fb7c in i_panic (format=format at entry=0x7f399407a0e8 "file %s: line %d (%s): assertion failed: (%s)") at failures.c:530
         ctx = {type = LOG_TYPE_PANIC, exit_status = 0, timestamp = 0x0, timestamp_usecs = 0, log_prefix = 0x0, log_prefix_type_pos = 0}
         args = {{gp_offset = 40, fp_offset = 48, overflow_arg_area = 0x7ffcff39b4e0, reg_save_area = 0x7ffcff39b420}}
#6  0x00007f3993f8105a in oauth2_request_start (set=0x560d08176150, input=0x7ffcff39b5d0, callback=0x560d08042b50 <db_oauth2_lookup_passwd_grant>, 
context=0x560d082ffe90, p=0x560d082b7eb0, method=0x7f399407a2c6 "POST",
     url=0x560d08178480 "https://xxx.b2clogin.com/xxx.onmicrosoft.com/B2C_1_ropc/oauth2/v2.0/token?scope=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", 
payload=0x560d082b7ed8, add_auth_bearer=false) at oauth2-request.c:201
         __func__ = "oauth2_request_start"
         pool = <optimized out>
         req = <optimized out>
#7  0x00007f3993f9870a in oauth2_passwd_grant_start (set=set at entry=0x560d08176150, input=input at entry=0x7ffcff39b5d0, username=0x560d082ffe38 
"user.name", password=0x560d082ffe48 "",
     callback=callback at entry=0x560d08042b50 <db_oauth2_lookup_passwd_grant>, context=context at entry=0x560d082ffe90) at oauth2-request.c:351
         pool = 0x560d082b7eb0
         payload = 0x560d082b7ed8
#8  0x0000560d0804368a in db_oauth2_lookup (db=0x560d08176060, req=0x560d082ffe90, token=<optimized out>, request=0x560d082ffba8, 
callback=0x560d080370b0 <oauth2_verify_plain_continue>, context=0x560d082ffba8) at db-oauth2.c:862
         input = {token = 0x560d082ffe48 "", service = 0x560d082ffe20 "smtp", local_ip = {family = 2, u = {ip6 = {__in6_u = {__u6_addr8 = 
"\303\376\374\322", '\000' <repeats 11 times>, __u6_addr16 = {65219, 54012, 0, 0, 0, 0, 0, 0},
                   __u6_addr32 = {3539795651, 0, 0, 0}}}, ip4 = {s_addr = 3539795651}}}, real_local_ip = {family = 2, u = {ip6 = {__in6_u = 
{__u6_addr8 = "\303\376\374\322", '\000' <repeats 11 times>, __u6_addr16 = {65219, 54012, 0, 0,
                     0, 0, 0, 0}, __u6_addr32 = {3539795651, 0, 0, 0}}}, ip4 = {s_addr = 3539795651}}}, remote_ip = {family = 2, u = {ip6 = {__in6_u = 
{__u6_addr8 = "*\300\070\226", '\000' <repeats 11 times>, __u6_addr16 = {49194, 38456,
                     0, 0, 0, 0, 0, 0}, __u6_addr32 = {2520301610, 0, 0, 0}}}, ip4 = {s_addr = 2520301610}}}, real_remote_ip = {family = 2, u = {ip6 = 
{__in6_u = {__u6_addr8 = "*\300\070\226", '\000' <repeats 11 times>, __u6_addr16 = {
                     49194, 38456, 0, 0, 0, 0, 0, 0}, __u6_addr32 = {2520301610, 0, 0, 0}}}, ip4 = {s_addr = 2520301610}}}, local_port = 0, 
real_local_port = 0, remote_port = 0, real_remote_port = 0}
         __func__ = "db_oauth2_lookup"
#9  0x0000560d08026436 in auth_request_default_verify_plain_continue (request=0x560d082ffba8, callback=0x560d0803e6f0 <plain_verify_callback>) at 
auth-request.c:1123
         passdb = 0x560d0814da40
         result = 22029
         cache_key = <optimized out>
         error = 0x560d082ffe38 "user.name"
         password = 0x560d082ffe48 ""
         __func__ = "auth_request_default_verify_plain_continue"
#10 0x0000560d0802071b in auth_policy_check (request=<optimized out>, password=<optimized out>, cb=<optimized out>, context=<optimized out>) at 
auth-policy.c:575
         pool = <optimized out>
         ctx = <optimized out>
#11 0x0000560d0802ff72 in mech_plain_auth_continue (request=0x560d082ffba8, data=0x560d0813d368 "user.name", data_size=30) at mech-plain.c:58
         authid = <optimized out>
         authenid = 0x560d0813d377 "user.name"
         error = 0x560d0813d320 "h\323\023\b\rV"
         pass = 0x560d0813d388 ""
         i = <optimized out>
         len = <optimized out>
         count = 2
#12 0x0000560d0802a197 in auth_request_handler_auth_continue (handler=0x560d082d1ae8, args=args at entry=0x560d08268e96 
"21\tdGhvbWFzLmZlcnJhcmkAdGhvbWFzLmZlcnJhcmkA") at auth-request-handler.c:738
         request = 0x560d082ffba8
         data = 0x560d08268e99 "dGhvbWFzLmZlcnJhcmkAdGhvbWFzLmZlcnJhcmkA"
         data_len = 40
         buf = 0x560d0813d320
         id = 21
#13 0x0000560d0801cc62 in auth_client_handle_line (line=0x560d08268e91 "CONT\t21\tdGhvbWFzLmZlcnJhcmkAdGhvbWFzLmZlcnJhcmkA", conn=0x560d08276d30) at 
auth-client-connection.c:228
No locals.
#14 auth_client_input (conn=<optimized out>) at auth-client-connection.c:311
         _data_stack_cur_id = 3
         line = <optimized out>
         ret = <optimized out>
#15 0x00007f3994051c29 in io_loop_call_io (io=0x560d0826f240) at ioloop.c:737
         ioloop = 0x560d08145f80
         t_id = 2
         __func__ = "io_loop_call_io"
#16 0x00007f3994053251 in io_loop_handler_run_internal (ioloop=ioloop at entry=0x560d08145f80) at ioloop-epoll.c:222
         ctx = 0x560d08148600
         events = <optimized out>
         event = 0x560d08148680
         list = 0x560d082ae620
         io = <optimized out>
         tv = {tv_sec = 0, tv_usec = 315566}
         events_count = <optimized out>
         msecs = <optimized out>
         ret = <optimized out>
         i = 0
         j = <optimized out>
         call = <optimized out>
         __func__ = "io_loop_handler_run_internal"
#17 0x00007f3994051ccc in io_loop_handler_run (ioloop=0x560d08145f80) at ioloop.c:789
         __func__ = "io_loop_handler_run"
#18 0x00007f3994051e50 in io_loop_run (ioloop=0x560d08145f80) at ioloop.c:762
         __func__ = "io_loop_run"
#19 0x00007f3993fc4df3 in master_service_run (service=0x560d08145dd0, callback=<optimized out>) at master-service.c:869
No locals.
#20 0x0000560d0801abf5 in main (argc=<optimized out>, argv=<optimized out>) at main.c:393
         c = <optimized out>
...


And "doveconf -n":
...
# 2.3.19.1 (9b53102964): /etc/dovecot/dovecot.conf
# OS: Linux 5.10.0-18-amd64 x86_64 Debian 10.13
# Hostname: relay-out1.domain.com
auth_cache_negative_ttl = 0
auth_cache_size = 40 M
auth_cache_ttl = 30 days
auth_mechanisms = plain login
auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_%@
auth_username_translation = %@
auth_verbose = yes
auth_verbose_passwords = plain
auth_worker_max_count = 100
disable_plaintext_auth = no
namespace inbox {
   inbox = yes
   location =
   mailbox Drafts {
     special_use = \Drafts
   }
   mailbox Junk {
     special_use = \Junk
   }
   mailbox Sent {
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     special_use = \Trash
   }
   prefix =
}
passdb {
   args = /etc/dovecot/dovecot-oauth2.plain.conf.ext
   driver = oauth2
   mechanisms = plain login
}
passdb {
   args = /etc/dovecot/dovecot-sql-account.conf
   driver = sql
}
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0660
     user = postfix
   }
}
userdb {
   args = /etc/dovecot/dovecot-sql-account.conf
   driver = sql
}
...


System OS is Debian 10, Dovecot installed from dovecot repository.

Many thanks
Urban


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