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cifs: replace snprintf with scnprintf
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a trivial patch that replaces all use of snprintf with scnprintf.
scnprintf() is generally seen as a safer function to use than
snprintf for many use cases.

In our case, there is no actual difference between the two since we never
look at the return value. Thus we did not have any of the bugs that
scnprintf protects against and the patch does nothing.

However, for people reading our code it will be a receipt that we
have done our due dilligence and checked our code for this type of bugs.

See the presentation "Making C Less Dangerous In The Linux Kernel"
at this years LCA

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Ronnie Sahlberg authored and Steve French committed Mar 5, 2019
1 parent 68e2672 commit 74ea5f9
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Showing 5 changed files with 19 additions and 19 deletions.
6 changes: 3 additions & 3 deletions fs/cifs/cifssmb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -139,8 +139,8 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
return -ENOMEM;

if (tcon->ipc) {
snprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
tcon->ses->server->hostname);
scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
tcon->ses->server->hostname);
rc = CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
goto out;
}
Expand Down Expand Up @@ -172,7 +172,7 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
continue;
}

snprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);
scnprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);

rc = CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
if (!rc)
Expand Down
6 changes: 3 additions & 3 deletions fs/cifs/connect.c
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Original file line number Diff line number Diff line change
Expand Up @@ -348,7 +348,7 @@ static int reconn_set_ipaddr(struct TCP_Server_Info *server)
cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
return -ENOMEM;
}
snprintf(unc, len, "\\\\%s", server->hostname);
scnprintf(unc, len, "\\\\%s", server->hostname);

rc = dns_resolve_server_name_to_ip(unc, &ipaddr);
kfree(unc);
Expand Down Expand Up @@ -2775,7 +2775,7 @@ cifs_setup_ipc(struct cifs_ses *ses, struct smb_vol *volume_info)
if (tcon == NULL)
return -ENOMEM;

snprintf(unc, sizeof(unc), "\\\\%s\\IPC$", ses->server->hostname);
scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", ses->server->hostname);

/* cannot fail */
nls_codepage = load_nls_default();
Expand Down Expand Up @@ -4203,7 +4203,7 @@ static int update_vol_info(const struct dfs_cache_tgt_iterator *tgt_it,
new_unc = kmalloc(len, GFP_KERNEL);
if (!new_unc)
return -ENOMEM;
snprintf(new_unc, len, "\\%s", tgt);
scnprintf(new_unc, len, "\\%s", tgt);

kfree(vol->UNC);
vol->UNC = new_unc;
Expand Down
14 changes: 7 additions & 7 deletions fs/cifs/link.c
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Original file line number Diff line number Diff line change
Expand Up @@ -103,9 +103,9 @@ parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
return rc;
}

snprintf(md5_str2, sizeof(md5_str2),
CIFS_MF_SYMLINK_MD5_FORMAT,
CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
scnprintf(md5_str2, sizeof(md5_str2),
CIFS_MF_SYMLINK_MD5_FORMAT,
CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));

if (strncmp(md5_str1, md5_str2, 17) != 0)
return -EINVAL;
Expand Down Expand Up @@ -142,10 +142,10 @@ format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
return rc;
}

snprintf(buf, buf_len,
CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
link_len,
CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
scnprintf(buf, buf_len,
CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
link_len,
CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));

ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
memcpy(buf + ofs, link_str, link_len);
Expand Down
6 changes: 3 additions & 3 deletions fs/cifs/smb2pdu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -173,8 +173,8 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
return -ENOMEM;

if (tcon->ipc) {
snprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
tcon->ses->server->hostname);
scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
tcon->ses->server->hostname);
rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
goto out;
}
Expand Down Expand Up @@ -206,7 +206,7 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
continue;
}

snprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);
scnprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);

rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
if (!rc)
Expand Down
6 changes: 3 additions & 3 deletions fs/cifs/smbdirect.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1550,7 +1550,7 @@ static int allocate_caches_and_workqueue(struct smbd_connection *info)
char name[MAX_NAME_LEN];
int rc;

snprintf(name, MAX_NAME_LEN, "smbd_request_%p", info);
scnprintf(name, MAX_NAME_LEN, "smbd_request_%p", info);
info->request_cache =
kmem_cache_create(
name,
Expand All @@ -1566,7 +1566,7 @@ static int allocate_caches_and_workqueue(struct smbd_connection *info)
if (!info->request_mempool)
goto out1;

snprintf(name, MAX_NAME_LEN, "smbd_response_%p", info);
scnprintf(name, MAX_NAME_LEN, "smbd_response_%p", info);
info->response_cache =
kmem_cache_create(
name,
Expand All @@ -1582,7 +1582,7 @@ static int allocate_caches_and_workqueue(struct smbd_connection *info)
if (!info->response_mempool)
goto out3;

snprintf(name, MAX_NAME_LEN, "smbd_%p", info);
scnprintf(name, MAX_NAME_LEN, "smbd_%p", info);
info->workqueue = create_workqueue(name);
if (!info->workqueue)
goto out4;
Expand Down

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