CVE-2024-38440

Netatalk 3.2.0 has an off-by-one error, and resultant heap-based buffer
overflow and segmentation violation, because of incorrectly using
FPLoginExt in BN_bin2bn in etc/uams/uams_dhx_pam.c. The original issue 1097
report stated: ‘The latest version of Netatalk (v3.2.0) contains a security
vulnerability. This vulnerability arises due to a lack of validation for
the length field after parsing user-provided data, leading to an
out-of-bounds heap write of one byte (\0). Under specific configurations,
this can result in reading metadata of the next heap block, potentially
causing a Denial of Service (DoS) under certain heap layouts or with ASAN
enabled. … The vulnerability is located in the FPLoginExt operation of
Netatalk, in the BN_bin2bn function found in /etc/uams/uams_dhx_pam.c …
if (!(bn = BN_bin2bn((unsigned char *)ibuf, KEYSIZE, NULL))) … threads
… [#0] Id 1, Name: “afpd”, stopped 0x7ffff4304e58 in ?? (), reason:
SIGSEGV … [#0] 0x7ffff4304e58 mov BYTE PTR [r14+0x8], 0x0 … mov rdx,
QWORD PTR [rsp+0x18] … afp_login_ext(obj=<optimized out>,
ibuf=0x62d000010424 “”, ibuflen=0xffffffffffff0015, rbuf=<optimized out>,
rbuflen=<optimized out>) … afp_over_dsi(obj=0x5555556154c0 <obj>).’